The Science of Star Wars: Chapter 2: Aliens
A black, triangular-headed alien with glimmering gold eyes pops up in the local cantina. An ancient, eyeless slug lurks within an asteroid. A sinuous snakelike creature with a periscope for a head prowls the Death Star’s garbage masher for tasty treats. One of the most delightful aspects of Star Wars is the constant appearance of bizarre forms of alien life.
Almost anywhere you go in “a galaxy far, far away,” alien life is there. You’ll either land in it, step on it, or get eaten by it. The skeleton of a of a Sandsnake on a Tatooine sand dune creates an echo of the past. A dragon-like creature lurks in an underwater cave on Naboo. Artoo falls into the swamps of Dagobah and is almost instantly eaten, and almost as quickly spit out. Wherever you go, whatever you do, there will always be an alien there to do it with you.
When Luke Skywalker entered that cantina twenty-two years ago, the way we thought of aliens and the way they were treated in science fiction changed forever. No longer were we expected to gawk in fascination at a single alien species; the universe, according to George Lucas, is filled with life. Not only do many planets develop life, but on any one planet, many different species evolve, just as on Earth. Even in environments as inhospitable as Tatooine, Hoth, or an asteroid, life finds a way to survive. But what sort of life would develop in these various environments?
If alien life is indeed plentiful, as recent scientific discoveries lead us to believe, will it look anything like Star Wars aliens? Is the universe likely to be home to glowing-eyed Jawas, wriggling Hutts, cuddly Ewoks, hungry Sarlaccs, gooey Mynoks, and goofy Gungans?
How alien are aliens?
On Earth, we’re presented with a huge variety of life – organisms with leaves, wings, trunks, claws, flippers, tentacles, hooks, antennae, horns, quills, scales, fur, fangs, shells, slime. Organisms that reproduce through spores, seeds, division, sex with another, sex with themselves. Organisms that live inside other organisms; organisms that live attached to the outside of other organisms; organisms that live in water, air, rock, dirt, blood, ooze. Over the history of our planet, tens of billions of different species have existed.
Dr. Pickover says, “When I gaze upon crazy-looking crustaceans; squishy-tentacled jellyfish; grotesque, hermaphroditic worms; and slime molds more alien than the wildest dreams of science fiction writers, I know that God has a sense of humor, and we will see this reflected in other forms in the universe.” Considering that such a variety of creatures developed on our single planet, it seems unlikely that aliens will happen to have human characteristics or form.
With two arms used to perform tasks, two legs used to walk, and a head with sensory apparatus, many Star Wars aliens have the general form of a human: Yoda, the Jawas, the Sand People, Jar Jar Binks, the Wampa ice creature, Greedo, Admiral Ackbar, the Ugnaughts of Cloud City, the lizard bounty hunter Bossk, the tentacle-headed Bib Fortuna, singer Sy Snootles, Lando’s copilot Nein Numb, Chewbacca, the Ewoks, the cantina band, and many other miscellaneous aliens in the movies. Yet Star Wars provides us with many non-humanoid aliens as well, offering a wider variety of aliens than any other science fiction movies, with Banthas, Tauntauns, Sandsnakes, Sarlaccs, Hutts, Dewbacks, Mynoks, space slugs, and many more.
These make the Star Wars universe feel real, vibrant, and unique. Dr. Michio Kaku, Henry Semat, Professor of Theoretical Physics at the City University of New York and author of Hyperspace and Visions, agrees. “In Star Wars, the aliens don’t look like us anymore. They tried to have aliens with different architectures. In that sense, Star Wars is more realistic than some of the stuff I’ve seen.”
But is this what alien life would really be like? The most likely alien life we’ll encounter will resemble terrestrial bacteria. Bacteria developed first on Earth about 3.85 billion years ago, and remained the sole type of life for billions of years. Multicellular organisms didn’t appear until about one billion years ago, and animals evolved only six hundred million years ago, quite recently in Earth’s life span. Even though complex life-forms are now common on Earth, bacteria still make up the majority of life on our planet. Dr. Stephens believes we’re going to find the same ratio of primitive to more sophisticated life everywhere in the universe. “I think what we’re going to find is enormous numbers of planets and moons where the first steps of life have occurred, even up to the formation of things that resemble bacteria.”
So we’d likely encounter many planets with primitive life-forms, and a much smaller number with more complex life. Dr. Jakosky comes to the same conclusion. “It took three billion years on Earth to go from single-celled organisms to multicellular complex organisms. That means that’s not a likely event. Once we got complex organisms one billion years ago, though, Earth experienced a rapid explosion of diversity of life. Once complex life develops, tremendous diversity is likely to arise.”
What would this complex life be like? To consider what alien life might look like, it’s helpful to think about how terrestrial life came to look like it does. Species are created through evolution. Random genetic mutations occur as organisms live and reproduce. If a mutation happens to be favorable, helping the organism to survive in its particular surroundings, it’s more likely to reproduce and pass that mutation on to offspring. If the mutation happens to be unfavorable, the organism may die before it has a chance to reproduce, and so the mutation will disappear from the gene pool. Evolution involves a lot of chance circumstances, both genetically and ecologically.
Dr. Jakosky calls these chance circumstances “accidents of history.” A mutation could occur that makes a fish much more fit for life in the tiny pond where it lives. Yet it happens to be born in a dry year, and before it has a chance to reproduce, the pond dries up and the fish dies, so the mutation is never passed on. At the same time, another fish is born that has a mutation that is. Normally, the first fish would eat this one for breakfast. Yet as the pond dries up, the second fish finds it can survive for brief periods outside water, long enough, in fact, to flop over to a larger lake a few feet away that doesn’t dry up. This odd fish, which can move between land and water, survives and reproduces, and perhaps becomes the ancestor of all vertebrates, including man.
If instead of a dry year it had been a year of heavy rains, that fish would never have survived, and quite different creatures might have evolved. Dr. Jack Cohen, reproductive biologist and consultant for the Mathematics and Ecosystems Departments at the University of Warwick, points out some interesting characteristics of the fish that came out of the water three hundred million years ago to become the ancestor of all vertebrates. “It had its airway crossing its foodway, and it had a reproductory system mixed with its digestive system. There were many fish that didn’t have those mistakes, and one of those could have crawled out of the water.”
Chance, then, has played a large role in our development, making us creatures that breathe and eat through the same opening, our mouth, and reproduce through organs intertwined with our excretory system. Many Star Wars aliens seem to share these mistakes – at least they appear to use the same opening to breathe and eat, which seems quite odd. We can only speculate on their reproductory systems. How these “accidents of history” might combine on another planet is very difficult to predict. Dr. Tim White, professor of integrative biology at the University of California at Berkeley, believes that “it’s hard for us to imagine other kinds of life.
“Animals adapt, through evolution, to their environment, and we don’t know about extraterrestrial environments outside our solar system. In addition, you have chance events that end up knocking things off-balance every once in a while, and thereby structuring the fabric of life and making its evolution unpredictable.” Even a planet similar to Earth would most likely give rise to significantly different organisms. In fact, scientists believe humans wouldn’t even have evolved here unless the dinosaurs were killed off by a huge meteoroid sixty-five million years ago.
Dr. White says, “You take away this event or that event, and we’re not having this conversation.” Most likely, aliens are going to be stranger than we can imagine. Dr. Pickover agrees. “Considering that octopi, sea cucumbers, tube worms, and pine trees are all very closely related to us, an alien would look less like us than does a squid.” So is there no way to tell what aliens might look like?
Well, aliens are life-forms, like us, and face some of the same problems we face – problems of movement, sensing and manipulating their environment, nourishing themselves, and reproducing. Solutions to these problems that are valid on Earth ought to be equally valid in “a galaxy far, far away.” Thus, even though alien life would have taken a very different evolutionary course and would have DNA quite different than ours – if it has DNA at all – it might end up with some similar characteristics. Life on planets has to deal with gravity, which will probably lead to organisms with a specific top and bottom. Sophisticated life that moves will probably have a front and a back. To sense their environment, organisms need one or more of the following abilities: to detect a useful spectrum of electromagnetic radiation (to see); to detect changes in the surrounding atmosphere (to hear and smell); to detect heat and evaluate surfaces (to touch); and to evaluate food (to taste). If an organism must seek out food, then it would make sense to concentrate these sensory organs at the front end of the organism.
To manipulate the environment, sophisticated organisms require appendages. To move through that environment, they need some method of locomotion. Some sort of symmetry will make mobility easier. But how likely is it that a creature might move using two limbs like a man, four limbs like a giraffe, a muscular trunk like a snake or a fish, wings like a bird or an insect, a tentacle like an octopus, or some other method?
We can get some idea of how common or likely a certain solution might be by examining how many times that trait independently developed on Earth. Solutions that developed in different times and places must be particularly useful or efficient. For example, flight developed three separate times on Earth: once with birds, once with insects, and again with bats. Eyes developed four separate times.
So these solutions may be a bit more likely to develop on another planet. Dr. Pickover points to three quite unrelated animals: a dolphin, which is a mammal; a salmon, which is a fish; and an ichthyosaur, which is an extinct reptile. “They all swam in coastal waters darting about in search of small fish to eat. These creatures have very little to do with one another biochemically, genetically, or evolutionarily, yet they all have a similar look. They are nothing more than living, breathing torpedoes. They have evolved streamlined bodies to help them quickly travel through the water. We might expect aquatic aliens that feed on smaller, quick-moving prey to also have streamlined bodies.”
Other solutions have occurred only once on Earth, making them seem less likely to occur on another planet. For example, while all land animals have developed methods of acquiring water, only one, the elephant, uses a long trunk. Dr. Stephens believes that the form these solutions take is largely determined by physical constraints, which in turn are consequences of the laws of physics, chemistry, and biology. For example, let’s consider fingers or, more generally, digits. If aliens arrive here in spaceships, how many digits are they likely to have?
An intelligent, space-faring race needs to be able to manipulate its surroundings with limbs, and digits at the end of those limbs. Dolphins may be intelligent, but they’ll never light a fire and never build a spaceship. The realities of the physical world make certain numbers of digits more functional than others.
“Is there an ideal number?” Dr. Stephens asks. “Clearly the answer is yes.” One digit is obviously not going to be terribly useful at performing complex tasks. Similarly, two digits aren’t very good, which you’ve discovered if you’ve ever tried to do anything delicate wearing mittens. Dr. Stephens says, “Three is some kind of minimum threshold if you’re going to do serious manipulations.” If three is the minimum, what is the maximum? “When you get up to seven or eight, I think you have a difficult time accommodating that many digits on the end of an extremity and things would start becoming awkward.” While we haven’t done experiments that might prove five is the ideal number, Dr. Stephens believes five likely is the ideal.
“What we’ve learned recently is that our amphibian ancestors did not have five digits but had six or seven digits. Evolution and selection chose five for us, suggesting five is some sort of ideal.” Dr. Stephens then believes that intelligent aliens would likely have five digits, as we do. Since certain physical constraints are valid throughout the universe, Dr. Stephens concludes that even though intelligent aliens might have evolved from vastly different organisms than we did, they may very well be humanoid. “The probability of finding an alien that looks like us is perhaps as high as 80 percent.”
Yet he seems to be in the minority. Dr. Cohen suggests the opposite is true. “Finding another planet with our kind of dinosaurs or people is more unlikely than finding a remote Pacific island on which the natives speak perfect German.” Aliens would have gone through an entirely different evolutionary procedure, suffering different “accidents of history,” which would have led to different adaptations. Dr. Pickover considers humanoid aliens “far-fetched. Some of the Star Wars creatures seem a little too human-looking considering the quite different evolutionary pathways we’d expect.” For Dr. White, the most troubling characteristic of intelligent aliens is that most of them are bipedal. “There is no necessary correlation between bipedality and high intelligence.”
Dr. Kaku believes there are only three key elements an intelligent alien must have. “An opposable thumb or tentacle of some sort, language to communicate, and stereo eyes to hunt and strategize. Other than that, all bets are off.” Dr. Jakosky agrees. “There’s no intrinsic evolutionary drive toward a human shape, even though we can make all these arguments about how wonderful we are.”
While the number of aliens with human characteristics may be high, Star Wars aliens embody many non-human characteristics as well. Do the aliens make use of more “common” solutions, which would make them more likely aliens; do they use solutions that occurred only once on Earth, making them seem unlikely to occur ever again; or do they use uniquely alien solutions?
Fuzzball or genius?
If we do find alien life, will it be intelligent? Star Wars abounds with intelligent aliens, from Chewbacca to Jabba to Greedo to Jar Jar to Yoda. When I speak of intelligence here, I mean intelligence comparable to the sophisticated self-conscious intelligence humans have. My iguana, Igmoe, is extremely intelligent, yet even I won’t claim that he has the powers of thought, reasoning, and understanding that we have – at least, he fails to appreciate Star Wars, which is a failing of intelligence in my opinion.
Some scientists believe that while alien life may be plentiful, intelligent alien life is much less probable. They argue that while evolution works through “survival of the fittest,” being smarter does not always make you more fit. Organisms can be very successful in surviving and reproducing without high intelligence. Cockroaches, for example, are an extremely hardy species and may well outlive man. If additional intelligence was an advantage for them, so the argument goes, then we should have seen them growing progressively more intelligent over the generations, and we haven’t. Of course, I don’t know anyone who’s administered an intelligence test to a cockroach. Dr. Jakosky agrees that evolution doesn’t necessarily encourage intelligence.
“Organisms tend to have a brain just big enough to handle their body and not a lot extra. We’re the exception.” He points out that in four billion years and tens of billions of species, only man has developed self-conscious intelligence, “so that says it’s an uncommon event.” Or in other words, it’s an uncommon solution to the problem of survival. Dr. Pickover sees our intelligence as an evolutionary accident. “I believe that alien life will be unintelligent and unable to build crafts to leave their world. This is the prime reason why the universe of Star Wars, which thrives with intelligent life, is unrealistic.”
Yet other scientists believe intelligent life may be more common. While intelligence within a particular species may not increase, scientists point out that as life has evolved on Earth into more complex, advanced forms, the size of the brain relative to the body has increased, and intelligence has increased. And while human-level intelligence may have only developed once on this planet, lower levels of intelligence developed independently in all the different classes of animals. Astronomer Carl Sagan argued that more intelligence is beneficial to any organism, helping it find food and cope with changes in its environment. In that case, intelligent organisms would have a better chance of survival. Thus intelligence would be a natural consequence of life and evolution.
Dr. Frank Drake, head of the SETI Institute, estimates ten thousand to a hundred thousand intelligent civilizations exist in our galaxy. But if intelligent alien life is common, then why haven’t any aliens dropped in on us? This question is known as Fermi’s paradox, and scientists have struggled for an explanation for more than two hundred years. Some of the explanations they’ve come up with?
- Alien civilizations self-destruct before they develop interstellar travel.
- Aliens do visit us, but they like to keep their visits secret. Word could get back to a pesky bounty hunter.
- The stars are so for from each other, visits are just too difficult and expensive. Maybe if we kicked in some money for gas …
- Earth is just too for from the bright center of the universe to draw alien tourists.
- Aliens prefer to stay home, put on a pot of stew, and observe us through the Force.
Do your ears hang low?
Of all the alien species we meet in Star Wars, we know the native planets of only a few. Without this information it’s difficult to say whether their traits are likely or not. Even with this information, it’s very difficult to draw any firm conclusions. For example, say giraffes are not a species on Earth but an alien species in the next Star Wars movie. We could speculate endlessly about the viability of such an alien and the bizarre environment that might have spawned such a creature.
That long, heavy neck? How unlikely! It would fall on its face. It must come from a planet of light gravity that allows it to survive with such skinny stick legs. The planet must be covered with trees that hold their leaves an enticing fifteen or twenty feet off the ground. These conclusions seem reasonable, yet every one is wrong.
Thus, any speculation about specific aliens can be little more than educated guesses at this point. One factor may help a bit. Since the aliens we tend to see in the movies are those that can survive in the same environments as humans, we can assume that they probably developed in environments not radically different from Earth. Now let’s examine some of our favorite aliens.
The Phantom Menace introduces the lovable goofball Jar Jar Binks, a native of Naboo. Jar Jar has the basic exterior characteristics discussed earlier for complex, intelligent life: a top and bottom, a front and back, bilateral symmetry, sensory organs, a method of locomotion, and appendages to manipulate the environment. Generally humanoid in shape, Jar Jar has a number of distinctive characteristics that actually make him a fascinating mystery. Clearly the “accidents of history” that guided the evolution of Jar Jar’s species were much different than ours, but led to a body form that generally has much in common with a human’s. His long muzzle gives him the look of a camel or horse, his long ears are a bit rabbitlike, and the patterning of pigment on his arms is reminiscent of a lizard. Jar Jar’s most prominent trait – literally – is his eyes. Popping out from the top of his head like two ears with an identity crisis, they are unlike the eyes of any Earthly creature. The unusual location of the eyes and their structure suggest that their position may be critical to the survival of Jar Jar’s species, the Gungans.
While we don’t know exactly where on Naboo the Gungans evolved or how, we do have terrestrial animals with some similarities that may illuminate Jar Jar’s situation. In the crocodile, the nostril openings and the eyes are the highest parts of the head. This allows the crocodile to float on the surface of the water, with most of his body and head submerged, and yet see and smell his surroundings. Thus the crocodile can wait, looking like a floating log, until a potential meal comes to the edge of the water for its last drink. Then with a quick snap, it’s mealtime. Perhaps the Gungans, or their ancestors, obtained their food by some similar method. Their nostrils are positioned high on their heads, though not as high as the eyes. Another terrestrial model offers a different possibility. Many crustaceans, as well as some insects and fish, have eyes on stalks. Eyestalks allow the eyes a great freedom of movement. While Jar Jar’s eyes are not on stalks and so can’t have the level of mobility of stalk eyes, his eyes still probably have some mobility, with muscles at the base of the eyes allowing them to tilt forward or back or twist to one side or the other.
In some creatures with stalk eyes, each eye is at the end of a rod of cartilage. At the base of the rod is a muscle that controls the movement of the rod. Thus the rod can be moved around, aiming the eye in virtually any direction. Since crustaceans tend to be slow-moving and are slowed further by the viscous water, they can’t dart their heads about quickly like birds to monitor their surroundings.
Jar Jar can move quickly, though. So it’s unclear what advantage moving eyes would have when he could move his head just as fast. Some mobility in his eyes, though, can potentially provide a wide field of view. If a creature is an herbivore, a wide field of vision is helpful to keep watch for predators sneaking up on it.
In terrestrial creatures, most herbivores get a nearly 360-degree view by having eyes that face to the side. If a creature is a carnivore, stereoscopic depth perception is helpful to precisely target and seize its prey. Carnivores then tend to have both eyes facing ahead. Jar Jar’s eyes do seem to face ahead when at rest, so he may have the best of both worlds: stereoscopic depth perception and a wide field of vision when needed. Another advantage of this construction is with the eyes removed from the skull, there is more room for the brain.
In many terrestrial species, brains and eyes must compete for skull space. The larger the eye, the greater the visual resolution. So larger eyes with sharper vision would be helpful to all creatures to survive. Yet the bigger the eyes, the less room is left for the brain. Birds, whose high-speed flying requires sharp vision, give up more skull space to their eyes than their brain. Removing the eyes from the skull would allow Jar Jar to have a bigger brain than a camel or horse. This solution to the skull-space problem, though, makes the eyes vulnerable to damage, rather than protected within bony sockets.
Dr. Stephens points out, “If you look at any vertebrate organism, the senses are quite well-protected by bone. Even the crocodile has a ridge of bone on top of its eyes. No vertebrate organism I can think of has any sensory organ hanging out there in the breeze without protection.” A fall on the head could get squishy, and a predator could tear Jar Jar’s tasty nuggets off in one bite. It seems the eyes must offer a significant advantage to make up for this danger.
His eyes yield yet further information. Animals that live in nocturnal environments must develop very sensitive eyes, eyes that have both very large pupils to allow in as much light as possible and specially designed retinas to detect the dimmest light. The light-sensitive retina at the back of the eye is normally made up of two kinds of cells, rods and cones. The rods are sensitive to dim light, while the cones handle bright light and provide color vision. Nocturnal animals have more rods than cones, which gives them better night vision. But when these animals also go out into bright light, they have trouble coping. Their pupils can contract to shut out most of the blinding light, muscles in the eye tightening to make that opening smaller.
But the specific arrangement of the muscles sets a limit on how small a round pupil can become. Even at its smallest, it may let in more light than a nocturnal creature can handle. A slit pupil, on the other hand, has its muscles arranged differently. When the pupil is dilated, it appears round, yet when it contracts, the muscles can close it down to a narrow slit, allowing only a tiny fraction of light to enter. The slit pupil is much better for nocturnal animals that also venture out in daylight. The crocodile, which is mainly nocturnal but also enjoys basking in sunlight, has a slit pupil. We can theorize that Jar Jar is mainly nocturnal as well. That must make it hard for him to adopt the diurnal schedule of his human companions.
Qui-Gon may find him prowling around at night, like you’d find your pet cat. Another clue to his lifestyle may be in his rather long, flexible neck. Many terrestrial animals have developed long necks, so it seems a fairly reasonable trait to find in an alien. Terrestrial animals use long necks for a variety of reasons. Giraffes use them to reach leaves high off the ground; storks use them to catch fish. We have a problem with any theory that has him using his neck to get food, though. A biped with two legs and two arms, like Jar Jar, would be much more likely to catch a fish with his hands, or to reach up with a hand and pull a branch with some tasty leaves down to mouth level.
Dr. Stephens asks, “Why would you develop a long neck if your grasp is twice as high as your head?” Perhaps, if he is operating like a crocodile, he waits until prey come close to his mouth and snaps them in, the long neck giving him additional mobility. Or perhaps the advantage of the neck is not to reach food, but to elevate the eyes even further. Camels have both long legs and long necks, which together serve to elevate their heads above the blinding, choking particles of desert sandstorms. A similar environmental condition could explain why Jar Jar’s body works so strongly to elevate his eyes. Perhaps a layer of ground fog tends to form during the night in the region where the Gungans evolved.
This occurs in different areas on Earth, such as river valleys, wetlands, or in coastal regions. The fog may tend to dissipate at a certain height, offering an advantage to those whose eyes are above the obscuring fog. Another interesting trait is Jar Jar’s long muzzle, which on Earth is common to quadrupeds. Quadrupeds tend to have long muzzles, since they need to use their mouths to hold and manipulate food as they eat it. Bipeds with arms, like humans, can use their hands to hold and manipulate food, so they don’t need a long muzzle. Jar Jar’s muzzle leads Dr. Stephens to “expect him to be very clumsy with his hands.”
Jar Jar definitely has some coordination problems. One final clue to Jar Jar’s nature is his huge, floppy ears. Large ears in terrestrial animals help animals radiate excess heat into the surrounding air. Desert-dwelling rabbits and other desert animals often have extra-large ears to help cool their blood. The large ears of African elephants serve the same purpose. Prominent veins in the ears help bring the blood close to the skin’s surface for cooling. In addition, the elephant can flap his ears to speed cooling. Jar Jar’s ears may work in a similar way.
They may also serve as communication devices. Elephants move their ears to assert their dominance over other males and to defend their territory. Perhaps the movies will give us further clues as to whether Jar Jar’s ears function in this way as well. We can thus theorize that the Gungans may have evolved in a hot climate where threatening predators lived. Hunting mainly at night offered one method for avoiding the heat, while their huge ears offered a method for dealing with heat when they come out during the day. Environmental conditions may have existed that made it difficult to see near ground level, so that elevating their eyes offered great advantages. Or the placement of their eyes may have helped them surprise prey. Yet the eyes are Jar Jar’s Achilles’ heel, and he must guard them at all times. One good tumble, and it’s lights out.
The dawn of Wookiee
Of all Star Wars aliens, the one I feel closest to is Chewbacca. Over seven feet tall and more than two hundred years old, Chewie is a hulking walking carpet, loyal, courageous, at times fierce, at times – when his nose is telling him things no one else seems to notice – a bit skittish.
According to the Star Wars Encyclopedia, Wookiees come from the forest planet of Kashyyyk, where they build cities a mile off the ground in the tops of massive trees, rather like Ewoks. Their long limbs would help them climb trees and swing from branch to branch. Claws on their feet, which are narrow and sharp, seem potentially helpful for climbing, though Chewie’s are clipped short – or perhaps they’re just retracted, like a cat’s. We can’t see if Chewie has claws on his hands, since, like most of his body, they’re shrouded in fur. Wookiees are very strong and can rip people’s arms out of their sockets, as Threepio well knows. They communicate through a language of cries, howls, and grunts.
While they can understand English, they are unable to speak it. Since from outward appearances Wookiees are basically humans covered in fur, they seem like viable organisms, in which all the pieces could fit and work together. Since body coverings like fur, hair, and feathers have developed independently several times on Earth, fur on an alien seems reasonable. Such body coverings help insulate a creature from external temperature changes, so Wookiees most likely face temperature fluctuations similar to those on Earth and use a similar solution to cope with them.
Chewie’s sharp teeth, front-facing eyes, and claws all point toward a carnivore. Chewie’s sensitive sense of smell would aid in tracking and locating prey. Humans hunt prey as well, though – at least our ancestors did – so we might question why Wookiees have a better sense of smell than we do.
Scientists have recently found that 72 percent of the genes that govern the formation of our olfactory receptors, the proteins that enable us to smell, are mutated so badly that the receptors don’t work. Our sense of smell has deteriorated greatly. Exactly when these mutations occurred is not yet known; they may have occurred during human evolution, or even earlier, before man developed. Apparently a high-powered sense of smell is not critical to man’s survival, and so those with less effective noses still survive.
In Wookiees, smell must play a more critical role. They may need – or have needed – smell to aid in the tracking of prey, which could hide in the dense forest. Or they may use their sense of smell to detect the emotions of other creatures. An angry snake, for example, has the distinctive smell of a wet dog, and knowing when a snake is angry could come in very handy. Wookiees may also use smell to send signals to each other, marking territory, indicating a desire to mate, or warning of danger. Since the vocabulary of Wookiees may be limited, scents could offer another method of communication. A dog’s sense of smell is one million times more sensitive than ours.
If Chewie’s is equal to or even greater than this, he may be getting a wealth of information through his nose. He could tell whether Jabba is hiding bounty hunters with blasters in the next room, a caseload of spices, or a frozen Han Solo. A strong sense of smell could even explain why Wookiees seem rather emotional. Scientists believe smell, more than any other sense, evokes strong feelings. The smell of the sweater of a loved one calls up a vivid sense of that person, triggering strong memories and feelings; the smell of fresh-baked chocolate-chip cookies triggers pleasure and excitement (in me, anyway). Odors can be informative, disgusting, delightful, frightening, and evocative.
Scientists believe that smell was one of the first senses to develop in terrestrial life. While information from our other sensory organs is relayed to the neocortex, the part of the brain involved in higher thought, scent information is passed directly to the most primitive part of the brain, the limbic system, and particularly an ancient structure called the amygdala. The amygdala is involved in storing emotional memories and can imbue events with intense emotions.
In our primitive ancestors, a smell triggered a strong emotion that in turn triggered a behavior: good food – eat! Today, while reason may keep us from acting on our desires – keep your hands out of the cookie jar – scents retain their direct line to our emotions. These brain connections are largely the result of evolutionary “accidents of history,” yet perhaps Chewie’s senses are wired in a similar way. With his more refined and acute sense of smell, scents may call up powerful emotions in him. While the Wookiees’ ability to smell is much greater than ours, their ability to speak seems much more limited. In this way, Wookiees are similar to chimpanzees. Chimpanzees communicate by expressions, gestures, and many distinct vocalizations, including screams, roars, hoots, and grunts.
They lack the ability to articulate the variety of sounds man can. Many elements contribute to man’s ability, including the lips, tongue, teeth, and the hard and soft palates on the roof of the mouth. The most critical element is the larynx, where the vocal cords are located. In humans, the larynx is lower in the throat than in apes. This change occurred as man began to walk erect, his brain size increased, and the location of the skull’s fastening to the spinal cord shifted to better balance the head. The lower position of the larynx creates a tubular cavity in which sound can resonate. Our relatively low-pitched speech arises from this cavity.
The structure of the chimpanzee’s larynx doesn’t allow it to make many of the sounds needed for human speech. But they have been taught to say a few limited words, such as “mama” just like in Planet of the Apes. Wookiees, then, may not have their larynxes positioned in a way that allows them to reproduce human speech.
And why should they? It seems much more believable that aliens wouldn’t be set up with the exact structure needed to reproduce human sounds. With his great number of similarities to us, Chewie doesn’t pose as difficult a puzzle as Jar Jar. Yet he does raise one compelling question: Why are Wookiees bipeds? Bipedality has evolved a number of different times on Earth, in dinosaurs, kangaroos, birds, and hominids. So it seems a trait we might possibly find in aliens. Yet is it a trait we would likely find in Wookiees?
We don’t know if the Wookiees always lived in the trees, or if they only moved there recently, once their level of technology allowed them to construct cities in the treetops. Yet it seems odd that a species that evolved on the ground would suddenly decide to move up into the trees. They would feel more at home on solid ground, the animals that served as food would be on the ground, and the conditions most favorable to their body structure and lifestyle would be on the ground. Climbing a mile down to the ground to hunt for dinner and a mile back up would make hunting a difficult proposition. It seems more likely, then, that Wookiees always lived in the trees, and that they’re able to satisfy all their needs without climbing down to the surface.
If the Wookiees did evolve in the trees, then, as seems more likely, we might wonder why they’d develop a bipedal gait. Walking upright doesn’t seem the easiest way to get around on a tree. Even if you could balance upright on a gigantic tree branch, why risk it?
Quadruped tree dwellers can move with great agility and speed. Dr. White would prefer to have more information before speculating about the evolution of the Wookiee. “In the unlikely event that I was presented with a real, rather than imaginative, Wookiee, I’d like to check out its living relatives and its ancestors, as much as we could figure out from the Wookiee fossil record, in order to explain where that creature came from.” In the absence of that information, though, can we learn anything from comparing Wookiees with Earth’s tree dwellers? A four-limbed creature needs many specific characteristics to walk on two limbs. The bones of the vertebral column, pelvis, leg, and foot need to have the proportions and shapes to withstand the stresses placed on them and allow easy movement. The muscles of the trunk and thighs need to develop the ability to balance and support the body’s weight and to propel it forward.
Scientists believe that a tree-climbing life helped prepare man’s ancestors to walk on two legs. Tree climbers tend to develop front legs somewhat different than their back legs, the front limbs reaching for food or branches, and the back legs supporting the weight of the body. Anthropologist Michael Seaman at Yale University points out that “Since they’re climbing up and down all the time, they hold their torsos erect.”
These adaptations actually serve as the preliminary changes necessary to prepare for a biped gait. So climbing creatures that evolve into bipeds seem reasonable. Yet the accepted theory for many years has been that a key element in the development of the biped gait in man’s ancestors, the hominids, was a change in climate. About four million years ago, the climate on Earth began to get drier. East Africa, which had been a moist woodland, began to change into an open grass-and scrub-covered savanna, the trees dying off. Man’s ancestors then had to leave the trees and adapt to life on the ground. In fact, footprints preserved in volcanic ash reveal bipedal locomotion had developed in this region 3.6 million years ago.
If the savanna theory is true, and bipeds did develop because a climactic change led hominids to move from the trees to the ground, one might then wonder how Wookiees – and Ewoks – ever became bipeds. Since they both are said to live in trees on heavily forested planets, and we’ve theorized that they evolved in these trees, the conditions seem incompatible with the savanna theory. In the last five years, though, the savanna theory has been challenged by new fossil discoveries and revised estimates of the climate during the development of hominids.
It’s now believed that Africa’s climate did not become particularly and until 2.8 million years ago, while we have recently discovered signs of bipedal locomotion as early as 4.2 million years ago. The recent discoveries of two previously unknown hominid species older than any before found are adding to the uncertainty. There are even indications that bipedalism may have developed independently more than once in different species of hominids, which would make it a somewhat more likely trait for aliens. While the savanna theory has been thrown into serious doubt, the problem is that scientists have no clear theory to replace it.
The leading contender appears to be one proposed by Dr. Owen Lovejoy of Kent State University. In his theory, the stimulus for bipedalism was the pairing off of male and female hominids into monogamous couples. The male began to provide food to the female and babies. When hominids developed this new strategy, it allowed females to give birth more frequently and males to gain exclusive sexual access to a female, which allowed successful pairs to pass their genes on to a large number of offspring. What does sex have to do with how you walk? Well, with this new lifestyle, the male needed to carry large amounts of food back to the female and children. To do this, he needed to walk upright and free his arms for carrying.
Dr. White believes “the Lovejoy model is the best available model.” If Dr. Lovejoy’s theory is true, it may reveal how Wookiees developed bipedal strides. While we don’t see much of the Wookiees’ lifestyle in the movies, key information is provided in the 1978 Star Wars Holiday Special, a two-hour TV show that is so awful it’s fascinating. Yet the show provides exactly the information we need. In this show, Chewbacca visits Kashyyyk, returning to the home where his wife Malla and son Lumpy live. And so we see the monogamous lifestyle that may offer a possible explanation of the Wookiees’ biped gait. My guess is that plenty of males would be willing to try walking upright on a tree branch if it meant they could have sex on a regular basis.
Just because it goes “ho ho ho” doesn’t mean it’s Santa
The award for most disgusting alien would have to go to Jabba the Hutt. Over sixteen feet long, with a bloated sluglike body, stubby arms, and a head like a giant pimple, Jabba slithers his way through the galactic underworld, with his home base a great palace on Tatooine. According to the Star Wars Encyclopedia, Jabba secretes mucus and sweat through his skin, making him slimy and slippery to catch by enemies. “His high exaltedness” enjoys snacking on marine life, which he keeps in a small aquarium beside the dais in his palace’s throne room. This suggests Jabba’s native habitat may be near the water. Although terrestrial slugs are only a few inches long at most, they offer the closest comparison we have to Jabba.
Slugs have soft, slimy bodies and tend to be nocturnal. While common slugs eat fungi and decaying leaves, some slugs are carnivorous, like Jabba, eating snails and earthworms. Slugs are hermaphrodites, containing both male and female sexual organs. The Encyclopedia tells us Jabba is the some. We should, in fact, call Jabba “it,” but that seems strange, so let’s go along with the Encyclopedia and call Jabba “him.” A slug can reproduce by taking on the male role and injecting sperm into another, or by simply combining its own sperm and eggs, in essence having sex with itself.
Jabba may have both of these options as well, which makes one wonder why he would be attracted to the scantily clad Leia. Dr. Pickover points out, “The chance of Jabba finding a human female alluring is about as great as you and I finding a female squid alluring.” I prefer a male iguana myself.
The belly of a slug is actually a single, tapered foot. The slug moves by generating waves of muscular contraction that ripple down the foot from the tail end to the front end. Also helping the slug along are tiny cilia on its foot, and a mucous sheet secreted by the front of the foot that provides a slimy carpet to help the slug glide ahead. This secretion of mucous causes the slug to lose a great amount of water, so all slugs need a moist environment to thrive.
Slugs and snails are both in the class Gastropoda, but snails developed in areas with irregular moisture, their shells a safe place to withdraw and contain their moisture in dry times. They can literally seal themselves in and wait years for rain. Slugs, without a protective shell, developed in areas that are moist year-round. To make sure they don’t run out of water, they conserve what they have, reabsorbing the water in their urine. But if slugs require moisture, how can Jabba survive on the desert planet of Tatooine?
In neither the special edition of A New Hope nor The Return of the Jedi do we see Jabba outside. Even as he is ordering Han Solo to his death in the Sarlacc, he remains below decks in his barge, without a clear view of the spectacle. I can’t believe Jabba would willingly miss seeing Han’s death. Jabba must need to remain in darkness most of the time, sheltered from the sun, the heat, and the dry air. Jabba’s preference for the dark goes along with a slug’s nocturnal lifestyle. Jabba’s slit-shaped pupils support the theory that Hutts are naturally nocturnal. Both his barge and his palace are kept dark, and he may have humidifiers of some kind keeping the air humid.
Of course such a method would be extremely costly on a desert planet where water is scarce. But he is Jabba the Hutt. And Tatooine, isolated and unwatched, may offer a very comfortable home for a crime lord. Jabba does seem able to get around, at least in a minimal way. In A New Hope, we see him in the Millennium Falcon’s docking bay, which certainly is not equipped with any special humidifiers. Here, Jabba’s size may give him an advantage over terrestrial slugs.
A large slug will dry out more slowly than a small slug. So Jabba could survive short periods of low humidity without any problems. The comparison to a slug does suggest several ways in which you might cope with a Hutt, if you find yourself face to face with one and don’t have a chain to strangle him with. First of all, don’t try to grab him, because the slime will help him slip away. And if you do manage to get hold of him, the Hutt probably has another trick up his sleeve.
Several kinds of land slugs have the ability to break off the back portion of their foot. This portion twitches violently, distracting the enemy, while the rest of the slug slides away. In A New Hope, Jabba seems shocked when Han jumps onto his back. I wonder if he was nearly startled into breaking his body apart. To kill a Hutt, you could always leave him in the desert to dry out. If you want to speed up the process, you can irritate his skin. Just as getting an irritating speck of dust in your eye makes your eye water, getting some irritating material on the skin of a slug makes it secrete huge amounts of slime. Spreading ashes or salt over the ground where a slug must travel works very well. The overproduction of slime dehydrates, exhausts, and finally kills the slug.
This could have saved Han, Leia, and Luke lots of trouble. Is it likely that an alien would look like a slug? The fossil record reveals that from more primitive forms, land-dwelling, carnivorous slugs developed independently several times on Earth. This suggests that these characteristics are fairly useful and efficient, and might possibly arise again on another planet. So when you head out on that space vacation, you may want to take a bucket of ash with you. And keep an eye on the right side of the Hutt’s head. The slug keeps its male reproductory organ there.
Slugfest
One of the most surprising aliens, and one of the most difficult to understand, is the space slug that lives inside one of the Hoth asteroids. The slug is hidden inside a cave or tunnel in the rock, and Han unknowingly lands the Millennium Falcon inside it. The slug seems to use a strategy similar to the Sarlacc on Tatooine, or the terrestrial ant lion or stargazer fish. The slug stays put with its mouth open, waiting for prey to fall in or come close enough to be grabbed.
The stargazer fish buries itself tail first in the sand, so only its eyes and mouth are visible – and only visible if you know what to look for. When prey swim by, it gulps them down. Many terrestrial organisms have such lifestyles, which seems to make the space slug fairly believable. And since we’ve discussed organisms that live deep underground on Earth, surviving on only rock and water, this suggests a narrow possibility that an organism could find sufficient nutrition on an asteroid.
Some asteroids are believed to have a layer of permafrost, and some reveal evidence that in the past they were heated enough so that their interiors melted. While it’s extremely unlikely that any heat would have lasted long enough to develop life, we could perhaps believe that under some unusual circumstances, the largest, hottest asteroid could have had some tiny stirring of life within. Yet the slug is clearly not feeding off of water and rock. It is a predator, hiding in wait with sharp teeth to grab and tear prey apart. This means there must be an entire ecosystem in the asteroids.
There must be creatures on whom the slug normally feeds – and I think it’s fair to assume they aren’t spaceships, since a pilot would “have to be crazy” to fly into an asteroid field. To support something as big as the space slug, these food creatures must be fairly large or fairly plentiful. Even if the slug lies dormant for long periods, it has to feed sometime. Yet we see no sign of organisms. And if there are microscopic organisms living deep within the rock, the slug cannot be feeding on them, since its mouth is pointed toward space. We might posit some other microscopic organisms somehow floating through space, the giant space slug feeding off them like a whale feeds off tiny plankton. But then why would the slug have such fierce teeth, or the ability to lurch out of its burrow and catch prey?
The Millennium Falcon seems too small for it to even notice. Its prey must be large and active. Let’s put aside for a moment the problem of what it eats. Say there is a large, constantly replenished supply of insane Corellian space jockeys that fly into the asteroid field, and have been flying into it for the last billion years. Could the space slug live in such an unfriendly environment? The slug would face a host of problems, including cold, meteoroids, and high-energy particles. But let’s focus on just one: pressure. Asteroids are too small to hold an atmosphere, so the slug is not sheltered in any way from the vacuum of space. Many people believe that the lack of pressure in space would cause living creatures to explode. The reasoning goes like this.
Our bodies are in a state of hydrostatic equilibrium with Earth’s atmosphere. At sea level, the atmosphere pushes in on us with a pressure of fifteen pounds on every square inch of our bodies. The fluids and gases inside our bodies exert an equal pressure outward. Any change in the pressure causes difficulties. If you are subjected to pressures less than 14.7 pounds per square inch, the body swells and bubbles of gas form in the blood. Divers go through some of these stresses when they move too quickly from high-pressure ocean depths to the lower-pressure surface, suffering the “bends.” If you quickly bring a deep-sea fish, which lives naturally at high pressures, up to the ocean surface, the gases dissolved in their body fluids will expand and blow the guts out through the mouth. The fish will explode. But that’s a fish.
The truth is that, while a pressure of zero pounds per square inch is very unhealthy for humans, it won’t make us blow up. We will suffer violently from the bends, all our internal gases would rush out of our body orifices – calling it farting just doesn’t cut it – and we’ll lose consciousness in only a few seconds. The proof came in 1971, when a Soviet spacecraft underwent accidental depressurization, exposing the three cosmonauts within to the vacuum. Their bodies did not explode or become deformed with exposure to the vacuum. Unfortunately, they died from lack of air.
Dr. Pickover estimates, “You should have fifteen seconds of useful consciousness before you pass out, and several minutes would be required before you die.” Apes exposed to a vacuum suffered some bleeding from areas with blood vessels very close to the surface, such as nasal passages, eyes, and lungs, but survived a brief exposure without permanent damage. Since humans and apes, which evolved on Earth, can survive the lack of pressure in a vacuum, it’s not unreasonable to imagine that a life-form could develop in the vacuum and survive there. An organism is, in essence, a contained packet of liquid and chemicals, like a Ziploc bag filled with water.
If the skin of the packet is strong enough, it can hold itself together. Since the slug appears to have no nasal passages or eyes, those possible sources of danger are eliminated. Another huge threat to the slug remains, however. The slug’s mouth and throat are also exposed to the vacuum. And if it doesn’t have some sort of airlock device to seal off its throat, the slug’s entire digestive system would be exposed to the vacuum. If the cells lining the digestive tract are as strong and protective as the outer cells of the slug, no problem. But the whole purpose of the digestive tract is to absorb nutrients. To do this, cell membranes must be permeable, meaning they must be able to pass materials in and out.
If they are, then the water in the cells will quickly evaporate into space. Indeed, when Han and the others step out into the slug’s throat, it’s moist and misty, suggesting the slug is losing water. Dr. Jakosky points out that “Any water lost would have to be replaced, presumably by ingesting new water, and it’s not obvious what the source would be.” Their excursion into the “cave” raises more problems. Any mist in the slug’s open mouth should be quickly sucked out into space. And since the slug’s mouth is open, the pressure inside the throat would be zero, which would disable Han, Leia, and Chewie in fifteen seconds, with all their bodily gases rushing out of them. That would make for an interesting scene. If the slug had an airlock device of some kind in its throat, which would allow food to be passed safely from the vacuum outside to a pressurized interior, we might be able to explain some of this. But when Han flies the ship back out of the slug, there is no such barrier.
Scientists do believe that life may be able to survive in space, but only hardy bacteria, probably in their dormant spore form, buried deep within the rock of a large meteoroid. Dr. Pickover points out that terrestrial bacteria were found to have survived on a camera left in the near-vacuum and extreme temperatures on the Moon for three years, when they were retrieved by the crew of Apollo 12. So might a more advanced life-form possibly live in the vacuum of space? Dr. Stephens says, “I don’t think the thing is even remotely feasible.” Yet Dr. Jakosky feels life may be more varied than we know. “I’d be reluctant to rule it out.”
How many aliens does it take to start a bar fight?
We discussed earlier how unlikely it would be for aliens from many different planets to survive in a single environment, such as the Mos Eisley cantina. Dr. Pickover raises an additional problem besides the environmental one. “The senses of aliens could be very different. Communication would be difficult.” He points out that every Earthly species perceives the world differently. “They can smell what we cannot, they can see what we cannot, they can hear what we cannot.”
Bees, for example, can see ultraviolet light invisible to us, and dogs can hear sounds undetectable by us. “If the organisms of the Earth were somehow able to describe their world to you,” Dr. Pickover says, “it would probably not be recognizable to you. It’s likely that we will never be able to fully understand alien ideas, just as we may never be able to understand the ‘language’ of dolphins.” Misunderstandings would be common unless one was in a very close relationship with an alien, like Han’s friendship with Chewbacca. Among humans from the some country, misunderstandings can arise easily enough. And among humans from different countries, language and culture can raise more problems.
Considering that aliens might see, smell, and sense different things than we do, it’s not surprising that an alien in the cantina might dislike Luke for seemingly no reason. It’s a short step from there to violence, and before you know it, the barkeeper has more body parts to clean up.
When the teddy bears have their picnic
We discussed the Ewok moon in the last chapter, considering various elements of the environment, and found that it could potentially support life. Let’s now look at the life that has evolved there. The Ewoks are short, furry creatures that look a lot like teddy bears. They walk upright, have short limbs, and short fingers and toes bare of fur. Each hand has an opposable thumb, as on humans, allowing the Ewoks to use tools. Their fingernails and toenails look like humans’ and are kept neatly trimmed. In Return of the Jedi we learn that they set traps for food, so they are predators. According to The Star Wars Encyclopedia, they are not only hunters but gatherers, which makes them omnivores. The Ewoks live in tribal groups, in villages built high up in great trees of the forest. The Ewoks’ small size would be a handicap in their development of tools and technology. It would allow them to wield a tool with only about one-twenty-fifth of the energy we could, making it hard to imagine how they might chop wood, build their homes, or kill an animal with one of those spears.
Their stubby fingers would make fine work very difficult. And their short arms make it hard to imagine the Ewoks starting a fire without burning their noses. But perhaps they’re particularly dexterous and patient. The terrestrial animals that Ewoks most resemble are koalas, Australian natives about thirty inches tall. These short, furry creatures have rounded ears that perch on top of their heads like the Ewoks’. The color and pattern of koala fur varies with the individual, also like the Ewoks’. Koalas have long fingers, including two opposable thumbs on each hand and one on each foot. These allow the koala to hold branches in a powerful, viselike grip. Koalas also have long claws to help them climb trees, and rough pads on the underside of their hands and feet to increase their traction while climbing. Koalas live in loose groups, but they each like to have their own tree to live in. They are vegetarians, living on eucaplyptus leaves.
Comparison to another terrestrial species, chimpanzees, is also illuminating. Chimps live in groups of fifteen to eighty and build nests up in trees, as Ewoks do, sleeping in them at night to avoid predators like lions and tigers. While chimps are mainly vegetarians, they will sometimes kill baboons or pigs for food. Chimps climb trees using their powerful, grasping hands and feet, each of which has an opposable thumb. They also get around by swinging with their long arms from branch to branch. We immediately see several key differences between Ewoks and these other species. Ewoks lack the characteristic traits of tree-dwelling vertebrates.
Dr. White points out that such animals have at least one of two qualities: “One, a bunch of sharp claws on their hands and feet that they cling onto the tree with. Two, a quadrumanous or four-handed anatomy. If you look at the foot of a primate, it looks like the hand, and it can grasp.” While Ewoks have opposable thumbs on each hand, their fingers are really too short and fat to use these thumbs to grasp any but the skinniest branch. And their feet have no opposable digit. It’s hard to imagine them scaling the huge trees that surround them, since their arms and legs could not wrap around them, and their nails could not dig into the bark. Anthropologist Michael Seaman finds the Ewoks’ body structure unlikely. “They don’t look like they’re really adapted for anything.”
We could argue that Ewoks don’t naturally live in those huge trees, just as humans don’t naturally live in apartment buildings. The Ewoks may have simply decided to move into the trees because it appealed to them, or because it offered them shelter from ground-dwelling predators. And they might use stairs and ladders to climb up there, rather than climbing up unaided. Michael Seaman finds this more plausible. “They may have evolved in a different type of forest or scurrying along the ground.” In a forest of smaller trees, their stubby limbs could be more effective.
They could put one foot on either side of the trunk and push their bodies up, like we climb a rope. If they did evolve in a forest of small trees, though, what happened to it, or why did the Ewoks move to this forest of giants? Perhaps the Ewoks simply multiplied and spread beyond their original habitat. Perhaps they were displaced by Imperial forces. Or perhaps they found the great trees better homes for more extensive, elaborately constructed villages, where they could really put on a great Jedi barbecue.
The small, the big, and the hairy
To consider the final group of aliens in the chapter, let’s return to the planet Tatooine. In Chapter 1, we theorized that the planet may have gradually dried over billions of years. How would life adapt to the desert environment? Surviving under such harsh conditions requires that organisms cope with extremes of temperature, survive with little water, and make the most of what water they have. On Earth, a wide range of animals and plants have adapted to life in the desert. They have many mechanisms for dealing with the lack of water, some external, some internal.
We have no information about what internal mechanisms might be employed by Tatooine dwellers, but we can deduce a fair amount about how well they’re adapted to a desert environment by their external characteristics. Small mammals tend to deal with the heat by retreating to underground burrows during the hottest part of the day. Only a few inches below the ground, the temperature can be significantly cooler. Since most of these creatures cannot pant or sweat to release excess heat, it’s critical for them to be able to escape the worst of the heat through behavior. This solution to the heat is limited to small animals, since the larger the animal, the harder it is to dig an underground burrow of sufficient size.
On Earth, the Jerboa or desert rat stays in such burrows during the day, where the temperature usually reaches no more than 68 degrees. When they come out at night, they move so quickly that they look almost like a cartoon Roadrunner blur. Their long hind legs allow them to leap like a kangaroo up to 6½ feet, and their large feet, a bit like snowshoes, help them move quickly over loose, sandy soil. This jumping motion keeps the contact between their feet and the hot sand to a minimum. Another trait they share with the kangaroo is a long tail that helps them keep their balance, even when they suddenly change direction. These traits allow them to move quickly with minimal exertion, a very valuable ability to have in the desert, where you want to get food and get home before sunup.
The Jerboa are quite good at functioning on little water. They extract all their needed water from the seeds they eat. They’re also much better at conserving water than humans are. Since they don’t pant or sweat to lower their body temperature, they don’t need as much water as we do. They excrete very little water, 20 percent less than a regular rodent. They also seal up their burrows during the day, locking in the moisture, and they sleep with their mouths lying next to stored seed, the moisture in their breath going into the seed to be eaten and recycled later.
While different deserts are homes to different species of small rodents, they all have these elongated back legs and shortened front legs, suggesting that these are very valuable characteristics to have. We see strikingly similar creatures in Mos Eisley in the special edition of A New Hope. They scatter as Luke and Obi-Wan drive into the city. These little Scurriers have short front legs, long hind legs, and long tails, and they usually run on their two hind legs, just like the Jerboa. While we do see them out during the day, this may be because their normal rhythms have been disrupted by man. Or perhaps daytime is the best time for scavenging on Tatooine, and a quick scurry from one air-conditioned building to another may keep them sufficiently cool.
Tatooine also has its share of larger species. Large animals take longer to heat up than their smaller counterparts, giving them more tolerance to heat. If you put a glass of iced tea and a gallon of iced tea out in the sun, you would expect the glass of tea to grow warm more quickly than the gallon. The smaller the object, the more quickly it will heat or cool. So once an animal is too large to burrow into the ground and must stay out in the sun, the larger it is, the better.
The Dewback is a reptile indigenous to Tatooine. We see storm-troopers riding this large, ungainly, four-legged creature. It has gray-green skin, a thick muscular tail, skinny legs, and bird-type feet, and performs a hitching waddle through the sand. While reptiles cannot withstand extremely hot temperatures, they do have several advantages over other types of animals in a desert setting. Their tough, scaly skin keeps water loss to a minimum, and their eggs have leathery shells that keep them safe from drying out. But desert-dwelling reptiles have a hard time dealing with the heat because they are cold-blooded. Their temperature is not internally regulated, as ours is, but simply rises or falls depending on the environment. This makes controlling body temperature one of the top priorities of any reptile. Exposed to the sun on a hot desert day, most reptiles’ temperatures will rise too high for them to survive. No reptile can survive a temperature of over 118 degrees.
My iguana, Igmoe, basking outside on our deck on a sunny 85-degree New Hampshire day will begin to pant after an hour or so, struggling to release excess heat. One method reptiles have of controlling their body temperature is to manipulate how much of their body is exposed to the sun. To maximize heating, they orient their long, cylindrical bodies with one side toward the sun. To minimize heating, they aim either their heads or tails toward the sun, exposing as little surface area as possible. Even then, though, temperatures will often rise above the point they can tolerate. To cope with this, most reptiles are active in the morning and evening only, retreating to rock crevices or burrows at the hottest part of the day.
Hopefully the stormtroopers don’t force the Dewbacks out into the sun at temperatures above what they can tolerate. The Dewbacks seem to cope reasonably well in the daytime situations where we see them. By manipulating their orientation to the sun, they can at least minimize the heat they absorb.
Another technique for coping with the heat is used by the agamid lizards. They have long legs that hold their bodies up off the burning sands. This offers a small bit of relief. In addition, the agamids, when stationary, always keep one foot in the air, constantly switching feet by turns in a circular cycle, so no one foot will get too hot. The Dewback’s skinny legs are tall enough to keep its underside a foot or two above the hot sands, so it can avoid that intense heat just like the agamids. I’d like to think it might also alternate feet, though we don’t see a Dewback long enough to observe this. The Dewback’s feet are its most troubling aspect. They are quite birdlike, with two toes pointing generally forward in a V and one toe pointing straight back. While the spread of the toes will help distribute the weight of the Dewback over a large area, making this type of foot superior to a hoof, the narrow toes will not be terribly effective at pushing through loose sand.
The camel, for example, has webbing between its two broad toes, and a foot as big as a plate. The arrangement of the Dewback’s toes suggests it does not normally live in areas of loose sand. Most likely, it lives in more stony regions of the desert, as many reptiles do. There, its tough bird feet would serve it well. But on loose sand they could easily get bogged down. I wouldn’t suggest stormtroopers ride them into the Dune Sea – or then again, maybe I would. One final interesting characteristic of the Dewback is its name. As night falls on the desert, the ground cools rapidly, cooling the air directly above it as well. Since cool air can’t hold as much moisture as warm air, the cool air deposits a thin layer of dew on the ground. What does that have to do with the Dewback? Well, one terrestrial reptile, the thorny devil, uses dew. Its skin cools rapidly as night falls, triggering dew to condense on its body just as it does on the ground.
This dew then runs into hundreds of folds in the thorny devil’s skin, the folds channeling the droplets of dew to the thorny devil’s mouth, where it can drink them. The Dewback may have a similar mechanism, dew forming on its back and running through the wrinkles and folds in its skin to a place where the Dewback can access it. Another reptile that lives on Tatooine is the Ronto, a longnecked beast of burden that looks like a new species of dinosaur. The Ronto has a number of characteristics that suggest it may be well adapted to desert conditions. The long neck of the Ronto is a characteristic it shares with a number of desert dwellers. Giraffe-necked antelopes not only have very long necks that allow them to eat leaves out of reach of other animals, but they can stand on their hind legs as well to reach vegetation even higher up. The Ronto may similarly use its neck to reach food, and we see it rear up on its hind legs.
The camel also has a long neck, as we discussed earlier. The height of the camel’s head – a result both of its long neck and its very long legs – elevates it above the level of most sandstorms. Sand particles tend to be of a rather uniform size. Thus when the wind blows at a certain velocity, the height that the sand can be lifted is fairly predictable. Depending on the ferocity of the storm, sand may rise from 3 to 6½ feet off the ground. Below that height, the air is filled with stinging sand that can invade your nose and mouth. Visibility is reduced to almost nothing. Above that height, the air is almost completely clear. In a sandstorm, a camel’s head rises above the level of the sand, allowing it to breathe and see with little problem.
The Ronto would share this advantage. The Ronto’s legs raise its body higher than the Dewback’s, so its stomach is about a Jawa’s height off the ground. A hot layer of air tends to form in the few feet just above the desert surface, and the Ronto’s legs would help to elevate it above this layer. In addition, the Ronto’s large round feet resemble those of a camel. About the size of a serving plate, they would help keep the Ronto from sinking into the sand. The Ronto’s neck is thick and bony, and it has a bony bulge behind its head. Different species of dinosaurs had odd bony structures in the head and neck area that may have served various purposes. The protoceratops had a bony growth on the back of its skull that looks rather like the bulge behind the Ronto’s head.
The triceratops had a wide bony frill like a crown protruding from the back of its head. By studying the chemical composition of this frill, scientists recently discovered that it helped the dinosaur radiate excess heat. Dr. Reese Barrick, from the University of North Carolina, tested various sections of the triceratops’s skeleton for levels of different oxygen isotopes. An isotope is simply a different version of an element, with either more or less neutrons in its nucleus than the element usually has. Oxygen normally has eight neutrons in its nucleus.
But sometimes a heavier oxygen is found with ten neutrons. The heavier oxygen tends toward cold locations, while the lighter tends toward warm. As the triceratops grew, the bones in colder parts of its body had more heavy oxygen incorporated into them, while bones in warmer parts of its light oxygen incorporated into them. Thus by measuring the levels of the different oxygen isotopes in various bones, Dr. Barrick could deduce the temperatures at different points in the triceratops’s body. What he found was that the frill was warm in the middle and cool on the outside, showing that it helped radiate heat away. Similarly, desert jackrabbits use their large ears to radiate heat, as we discussed in connection with Jar Jar.
The jackrabbits’ ears have a dense network of blood vessels that bring the hot blood near the surface of the skin and allow it to release its heat to the environment more quickly. The cool blood then returns to the interior of the body, cooling the rabbit. Scientists discovered signs that the triceratops’s frill similarly had a network of blood vessels crisscrossing it. While scientists aren’t as certain about the purpose of the protoceratops ‘s bony bulge, one possible explanation for it – and for the Ronto’s oddly shaped head and neck is that the structure helps to radiate excess heat and keep the animal cool. Another large species on Tatooine is the Bantha, an elephant-sized mount used by the Sand People. While Banthas are not native to Tatooine, they appear to function quite well in the desert heat. Their most striking characteristic is their long, thick fur.
You might think that fur would be a horrible hindrance in the desert, overheating the Banthas like a fur coat. Yet fur insulates an animal, keeping out excess cold or heat. Many desert animals have fur, from the jerboa to the antelope to the camel. In the desert, the sun’s heat is actually absorbed by the fur on the animal’s back, preventing it from penetrating deeper into the skin. The hair on a camel’s back has been measured at 158 degrees, while the body temperature of the camel was only 104. The Bantha’s fur would certainly help it cope with the heat. The Bantha also has a long, furry tail. While we see it dragging along on the ground, it may be capable of significant movement, as most animals’ tails are. The Namib ground squirrel fluffs out its tail and holds it up over its head like a parasol, to shelter itself from the sun.
Perhaps the Bantha does the same. There’s one more nonhumanoid Tatooine dweller we have to discuss. The Sarlacc, according to the Star Wars Encyclopedia, is not a native of Tatooine, but seems to function in the desert climate just fine, digging itself into the ground and waiting for prey to come. We can’t be sure how big the Sarlacc is, but it must be fairly large to have such a huge appetite.
While burrowing seems limited to smaller animals on Earth, the Sarlacc somehow manages to get its huge bulk into the ground. For a terrestrial model for this kind of behavior, we look to a much smaller animal, the ant lion. Ant lions live in a variety of climates and are common in the southwest United States. In their larval stage, ant lions have a large head, spiny jaws, and a bristly body about ½ inch long. Moving backwards, the larval ant lion traces out a circular pattern, spiraling steadily inward, digging deeper and deeper, until it creates a steep, conical pit in the sand and buries itself at the base of it. All that remains visible are long, curved jaws that lie open waiting for prey. When an unlucky ant comes up to the edge of the pit, the sand collapses, and it falls down into the trap.
The ant – much like Lando Calrissian – finds it can’t climb out of the pit. The sides are angled so they crumble when the victim tries to crawl out, which is just what happens when Lando tries to climb out of the Sarlacc’s pit. In the rare event that the prey looks like it might escape, the ant lion flicks sand at it, triggering an avalanche that brings the victim tumbling into its hungry maw. The ant lion snaps its jaws shut, injects a paralyzing poison and digestive acids into the victim, then sucks out its vital juices. When the ant lion is finished, it flings the carcass out of the pit with a flick of its head. Although the body of the prey isn’t digested inside the ant lion for one thousand years, as is said of the Sarlacc, any juices it has extracted from the prey do remain in the ant lion’s body, since it has no method of excreting waste products.
It’s not until the ant lion transforms into its pupal stage – the inactive stage between larva and winged insect – that it can eliminate waste. This means that the ant lion must hold all its waste for its entire larval lifetime: three years. And I thought sitting through a movie could be tough.
Did you leave your headlights on?
Tatooine has two indigenous humanoid species, the Jawas and the Sand People, also known as Tusken Raiders. We have never seen a Sand Person without his protective mask or wrappings, so it’s hard to say whether they have specific characteristics favorable for desert living. Obviously they need artificial aids to survive in the harshest desert conditions, just as we need aids – coats, gloves, and boots – to survive in the winter. If a species is intelligent enough to use artificial means for survival, they don’t need to be naturally as well adapted to the environment to survive. So aside from concluding that the Sand People are intelligent, we can’t tell much more.
The Jawas also remain rather mysterious, swathed in robes from which their bright eyes pierce. The Jawas’ hands appear furred, and the Star Wars Encyclopedia calls them “rodentlike,” so we might conclude they are a furred mammal of some kind. They’re hanging out among rocks and caves when they ambush Artoo. Perhaps they take shelter in caves during the heat of the day – or at least they may have lived this way before they had large air-conditioned transports for their comfort. The Jawas’ most striking feature is their glowing eyes. While those twin lights do at first impress us as eyes, though, it’s not clear that this is truly what they are.
They may be artificial, a tool, like a coal miner’s light, to assist them in seeing into caves and other dark places. Yet if that is so, why do they keep them on during the day? So perhaps we were right in our initial impression, and these two glowing disks actually are their eyes. Let’s consider how eyes work. Eyes are sensitive light-reception devices. Light from the environment enters through the pupil, and that allows us to see our environment. If the eyes themselves glow like a flashlight, this intense outgoing light will interfere with the incoming light, in essence washing it out.
Dr. Pickover offers an analogy. “How well could we hear if our ears emitted a continuous sound?” Instead, the eyes and lights could be separate organs, one to receive light, the other to emit it. Dozens of terrestrial organisms emit light, including fireflies, earthworms, algae, fungi, jellyfish, crustaceans, and fish. Various chemical reactions can produce a bioluminescent glow. The most brilliant light from a single creature probably comes from the Caribbean fire beetle, which has a heart-shaped orange light on its stomach and two yellow-green lights on its shoulders.
Women even put fire beetles in their hair as decorations – an idea, perhaps, for George Lucas, in his quest for unusual female hairstyles. The greatest collective light display is put on by male fireflies in Thailand, who gather in rows of trees and put on an impressive show of synchronized flashing to attract females. The most useful terrestrial animals with which to compare the Jawas are deep-sea fish. Two-thirds of all deep-sea fish are bioluminescent.
In the dark depths where a deep-sea fish lives, the lights on its own body may help it attract prey or mates, while the lights on other fish help it spot potential mates, recognize predators, and keep close to its school. These fish have light-producing glands called photophores. The photophores are composed of many tiny tubules, in which light-producing bacteria are confined. The bacteria and the fish live in a symbiotic relationship, the fish providing the bacteria a tasty enzyme to eat, the bacteria, in the chemical reaction that occurs when they eat the enzyme, producing light for the fish. Two fish, Anomalops and Photoblepharon, known as lamplight fish, have photophores beneath each eye.
These photophores can even be rotated in and out of a bony socket on the fish’s face, like headlights on a fancy car, so the fish can make the lights “blink” by moving them in and out, or the fish can hide by tucking the lights inside. Muscles can even aim the photophores a bit more ahead, so they can function more like headlights. At chow time, the fish gather with their school and their lights illuminate the immediate surroundings, allowing fish to see the plankton they feed on. Looking at these fish head-on, the photophores look like two glowing eyes.
If the Jawas did evolve in caves, their lights could serve the same function. Even in environments that aren’t completely dark, organisms find luminescence an advantage. One of the main uses of luminescence is to help attract the opposite sex. The female annelid fireworm releases streams of glowing eggs in the ocean. The males are attracted to the eggs, flash a light in response, and release their sperm.
If the Jawas’ lights serve this purpose, they all seem to be constantly looking for love. Bioluminescence can also serve more devious purposes. The females of one species of firefly mimic the flashing pattern of another. When the males show up ready for action, the females, not interested in mating at all, gobble them up. Similarly, the Jawas might use their lights to lure prey close. The ponyfish has glowing cells along the underside of its body. When predators below look up at the ponyfish, the glowing cells help the fish blend in with the light-mottled surface of the water above. Perhaps bioluminescent fungi grow inside the caves, and the Jawas’ headlights help them blend in with the cave wall, camouflaging them from predators.
The lights might be particularly useful in the desert. Before, we talked about how the camel’s height – and the Ronto’s – lifts its head above the level of sandstorms, allowing it to see and breathe. Jawas, as short as they are, will be completely immersed in a sandstorm. Many short animals can move very quickly to get to shelter in times of need. The Jawas don’t seem particularly fleet of foot, though. If the Jawas’ lifestyle requires they travel significant distances from home to find food, they could be caught out in a sandstorm. In such a case, their glowing eyes could serve as beacons, helping the Jawas find each other.
So what good is it to find your friends in a sandstorm if you’re all lost? The camel may shed some light on this. Camels out in the heat of day huddle together. This seems odd; we might expect them to stand separately. But remember that a small animal will gain or lose temperature more quickly than a large one. When the camels group together, they are making themselves, in essence, a single, larger organism. So their temperature is affected less by the environment.
Similarly, Jawas in the extreme heat and dehydrating winds of a sandstorm might want to find each other so they can huddle and create a larger collective organism, perhaps helping them survive until the air clears.
At home in the jundland wastes
Finally, let’s consider the human settlers who live on Tatooine. How do humans cope in desert environments? Tatooine residents seem to favor thick hooded cloaks and ponchos. Obi-Wan, Qui-Gon, Luke, the Sand People, and even the Jawas seem to prefer this type of dress. You might think that you’d want to wear as little clothing as possible in the desert heat (or just enough to avoid a sunburn). But heavy robes provide the same insulation that the fur of animals does, helping to moderate the temperature beneath from extremes of the environment.
Bedouin Arabs wear thick robes and head wrappings for the same reason. Loose clothing that traps a layer of air beside the body is the best. Many people believe white clothing is much better to wear in the hot sun, since white is better at reflecting heat than black. This is only partly true. White does reflect visible light, while black absorbs it. Yet most of the heat in the desert comes not from visible light but from lower frequency infrared light. Infrared light is absorbed as well by white clothing as it is by black. Thus the brown cloak of Obi-Wan and the brown cloaks of the Jawas are perfectly suitable to the desert. Even with such clothing, though, humans must constantly struggle to survive in the desert.
During sandstorms, the temperature rises and the air becomes very dry. A person can lose up to a quart of moisture from his body in an hour. Without lots of drinking water, a person can die within a few hours, literally drying into a mummy. And conditions aren’t much better even when it’s not a sandstorm. Humans cool themselves by sweating, which quickly depletes their bodies of water. If Luke Skywalker were abandoned out on the desert at twin-sunrise with no protective clothing or shelter, he would sweat away up to twenty-one pints of water before nightfall.
His body would draw water from his fat, tissues, and eventually his blood. As his blood thickened, his body temperature would rise, as if he had a fever. Blood circulation helps to cool blood, by bringing it just underneath the skin where it can radiate heat away. Thus impaired blood circulation makes matters even worse. He would not survive a single day.
Uwe George tells the story of a couple visiting the Sahara. They decided to drive their car from a large oasis to a small oasis twenty miles away. They arrived safely at the small oasis, and after a visit turned around to drive back to the large oasis. They assumed their return trip would be as uneventful as the initial one had been, so they didn’t bother to fill their water bottles.
They also forgot to fill their gas tank. They ran out of gas ten miles from the large oasis. The woman decided to wait in the shade beside the car while the man went ahead to the large oasis for gas. When the man returned five hours later with the gas, Uwe George says, “She was still sitting there. But she had perished of thirst.”
Hopefully Luke keeps his speeder stocked with water at all times, in case of such a situation. The desert is not friendly to machines, either. Sand mires cars in dunes and chokes up car engines. While we’re on the subject of the speeder, I can’t imagine why one would use an open vehicle to travel in the desert. Loose sand would irritate ones eyes and nose, and a sandstorm would cause major breathing problems. How could one live comfortably in such a place?
The home of Owen and Beru Lars, where Luke lives, is built into the ground. Desert dwellers on Earth have used a similar strategy to create cool homes. In the Tunisian village of Matmata, over one hundred homes have been tunneled into the ground, each with a central courtyard open to the sky. Such homes are usually two stories deep, the upper story used for storage, the cooler lower story used for living. Just as animals dig burrows to keep cool, humans do the same.
When you look down from ground level into the circular courtyard, you see numerous doors and windows in the walls, and stairs connecting one level to the other. The scenes in Owen and Bern’s home were actually filmed inside such a structure, the hotel Sidi Driss in Matmata. Having a courtyard about thirty feet below ground level means it will more often be in shade, receiving the direct heat of the sun only when it is nearly overhead. The courtyard also tends to retain cool night air and keep the inside of the house cooler during the day. Thick walls further insulate the inner rooms, creating a home significantly cooler than one built above ground.
We see those thick walls again in Anakin’s home in Mos Espa, helping to insulate the interior even though it’s not below ground. Apparently, air conditioning is out of fashion on Tatooine. Star Wars presents a universe filled with an amazing variety of life, filling every available ecological niche. While scientists remain uncertain about what sort of alien life we will find, it is sure to include species as bizarre as those we see in the movies, and probably species even more bizarre.
Linked from Fictional aliens