Lab Notes
Alien vs. Predator vs. Credibility

A good action movie can be as refreshing as a two-week vacation. A good science-fiction movie can be as mind-expanding as a year of college—the world-building, the thoughtful attention to detail, the resonance with timeless themes of the human spirit. ... And every now and then, maybe once or twice a decade, a movie comes along that hits both notes perfectly. Alas, Aliens vs. Predator: Requiem is not the one.

For some unfathomable reason, 20th Century Fox seems intent on murdering one of its most valuable franchises. AvP:R is the eighth movie to wear either the Predator title or the Alien one, and it's the fifth in a row to be really, surprisingly, abysmally bad. This is betrayal enough, given the high budgets, the quality scripts and the critical and commercial success of the first two Alien movies, and of the original Predator. Don't they rate sequels a little lower on the suck scale? What really kills me, though, is that Alien vs. Predator was first and foremost a comic-book crossover series. Between its debut in 1992 and the airing of the first AvP movie in 2004, Dark Horse released more than 1,500 pages of graphic novel, in 10 different series from a dozen top writers. Additional plot, texture and backstory were added in novelizations and video games, creating a rich trove of market-tested source material whose popularity is undeniable.

But the AvP movies chucked all that in favor of low-budget slasher-movie nonsense set right here on 21st-century Earth. For God's sake, people, if you're going to reinvent the wheel, at least make it round! And once the wheel is reinvented, how many times do you think you can retread it? Putting children, babies and pregnant women in harm's way may increase the gore factor, but it's not what I call new material.

Worse still, this latest movie plays fast and loose with the known biology of both the xenomorphs (aliens) and the Yautja (predators). We know from previous films, among other sources, that the predators like it hot. Indeed, they visit Earth mainly in the tropics, and only then during the hottest years. Apparently, temperatures below about 40 degrees Celsius (104 degrees Fahrenheit) are uncomfortable to them. They also like humidity, preferring to hunt their prey in rain forests. In a pinch they'll drop down in Los Angeles, where the average nighttime summer humidity runs about 55 percent, but it's clearly not their preferred range.

This makes Gunnison, Colo., a particularly unlikely place for a trophy-hunting expedition; it's a dry, frigid mountain village where the highest recorded temperature—ever!—was 36 C (98 F), and typical midsummer days peak closer to 26 C, barely above room temperature. Now, I can maybe believe a pissed-off Yautja could patrol the area in its high-tech chameleon spacesuit, but would it really strip off that armor for a mere display of machismo? Especially during a rainstorm, at night, in the middle of October? At least I assume it's October; the movie opens with a father and son hunting deer with a rifle, the legal dates for which are available to anyone with a telephone, a library card or an Internet connection. I'm going out on a limb here by assuming that between directors Greg and Colin Strause and screenwriter Shane Slaerno (Armageddon), someone bothered to look this up! This of course begs the question of why the trees still have their leaves and no one has their Halloween decorations out, but never mind about that.

On the plus side, the forested mountains of Gunnison County provide a familiar habitat for the acrobatic Predator to swing around in. We're even treated to a brief view of the Predators' home planet, but what we see is curiously urban and dusty—a sort of Chichen-Itza-meets-Mos-Eisley-spaceport. I can only imagine that around the corner, just outside the camera's view, are the towering, dew-soaked jungles the Yautja love so much.

A Lamarckian evolution revolution

Another serious problem I had with this movie was the fact that the xenomorphs show up on infrared. We know they're cold-blooded because they don't register on the thermal imagers of the space marines in Aliens. This is a problem for our friend the Predator, because his vision is based on heat and is easily fooled by cold objects. The xenomorph is also capable of remarkable stealth, making it difficult to locate by sound alone. Instead, it has to be tracked by its movements—a major plot point in previous movies—and is nearly impossible to detect when not in motion.

As in previous films and comics, though, the aliens get to show off one of their most interesting qualities: Lamarckian evolution. Before the rules of natural selection and Mendelian genetics were known, and long before the discovery of DNA, a Frenchman by the tongue-twisting name of Jean-Baptiste-Pierre-Antoine de Monet, who also held the title Chevalier de Lamarck (that's "knight of Lamarck"), proposed that traits acquired during an organism's lifetime could be passed along to its offspring. This theory was discredited for hundreds of years, and (as often happens in science) recently recredited when biologists learned about "epigenetics"—patterns of gene markers called methyl groups that our bodies use to turn certain genes on and off. As it turns out, our epigenome evolves in real time, in response to the chemical and physical and emotional stresses in our environment over the course of our lives, and many of these changes pass into the germline cells (the cells that produce eggs and sperm) and can persist for generations. Believe it or not, when rats are trained to run mazes, their offspring learn the same tricks faster! Similarly, identical twins who are separated at birth grow up less physically identical than twins raised in the same environment. In both cases, we have methyl groups to thank for it.

Still, here on Earth the epigenome controls only subtle changes in metabolism, immunity and physical development. By contrast, the xenomorphs seem to have elevated this quality to a high art; the aliens that gestate inside a human host grow up looking roughly humanoid, with two arms, two legs, a head, a lipped mouth, etc. In Alien 3, though, a xenomorph that grew inside a dog ended up quadrupedal, and the Aliens vs. Predator comics introduced us to the "predalien," a dreadlocked, claw-faced monster that gestates inside a Yautja who was a bit too slow or careless on the hunt. Too, it seems to me that the first alien—the one encountered by Ripley's crew in Alien—was slow and clumsy compared to the ones in later movies. I suspect they're able, epigenetically speaking, to adjust their reflexes to match—and exceed—those of the local prey. Presumably, later generations are also better adapted to human environments at the chemical level.

We are by no means the only thing they can eat, though, and our atmosphere is not the only type that can sustain them. They seem equally at home in air and water, and can survive (and continue functioning) for brief periods in total vacuum. The planet where they were first encountered—LV426 or "Acheron"—originally had a methane atmosphere. That wasn't their native habitat, but it didn't kill them either. Also, interestingly, we know from the original Alien movie that the facehugger's body chemistry includes silicon as well as carbon. This is presumably true of the adult aliens as well. However, their internal biochemistry is extremely adaptable, as science officer Ash remarks. They seem to have multiple chemical pathways to absorb energy and nutrients, and are able to grow rapidly even in environments that are, for their purposes, pretty marginal. Like any other organism, they die off without a food supply, but their eggs can lie dormant and viable for tens of thousands of years at the very least—long enough for their expired hosts to turn into fossils.

But where do they come from, that such crazy adaptations are necessary?

Nature nutured

The alien, in its original H.R. Giger incarnation and its later queen, dog and predalien forms, is known to retreat from fire and superheated steam, and while it's not affected by Antarctic cold, it does freeze solid at liquid-nitrogen temperatures. Xenomorphs are cold-blooded, but the nests generate their own internal microclimate, which again is fairly warm and wet by human standards. Still, all the evidence suggests that the xenomorphs are not related to the Yautja. Their homeworld likely experiences large swings in temperature—from well below freezing to just below the boiling point of water. More puzzling is the alien's ability to tolerate vacuum. How and why would it evolve an adaptation like that? I'm guessing the planet's air pressure varies along with its temperature, so that mountaintops—warm and habitable in the hot season—periodically find themselves in a Mars-like environment for a few hours or days. Then again, it seems the entire ecosystem sometimes dies off, or dies way back, and takes thousands of years to recover.

I'm picturing a high-gravity world, somewhere between Earth and Neptune in size, that orbits a larger gas giant that occasionally eclipses the sun. The atmosphere contains Earth-like levels of oxygen, but also carbon dioxide and large amounts of other reactive elements like sulphur and chlorine. Steam would be a major component, but it would all settle out in the cold season, creating vast temporary oceans that briefly iced over. The world must also be windy enough to support a permanent haze of fine-ground silica and coal dust. This is actually a source of nutrition to the xenomorph, and also serves to obscure the sunlight at ground level, so that (like the blind cavefish of North America), the creatures develop without eyes. How do they perceive the world around them so accurately?

The ecology of the planet must be extremely competitive—much more so than any reef or rain forest here on Earth—because the xenomorphs would wipe it all out in a month if there weren't other tough creatures (microbes, parasites, carnivorous plants and animals, etc.) capable of keeping their population at least partially in check. I'm guessing a human visit to this world would be extremely short and extremely unpleasant! Still, the xenomorphs must be close to the top of their food chain, because intelligence is one of their survival traits. They don't seem to have any technology, or anything we would describe as a culture, but they do clearly possess an unusual level of animal cunning. They can talk among themselves, formulating and executing a hunting plan, so they must be at least as smart as wolves, and because they figured out how to cut the power on Ripley and the space marines they may even be as bright as apes, at least when the big-brained queen is around to tell them what to do.

The other really, really noticeable thing about the xenomorphs is the acid they "bleed." In my opinion this may not be their actual blood, but a part of their immune system, like lymph, or a natural defensive armament, like the acid of the bombardier beetle. Still, when their skin is penetrated, the xenomorph bodies squirt out a pressurized fluid that rapidly dissolves metal, plastic and flesh. The facehuggers have no problem melting their way through a spacesuit visor. However, a glass jar can hold them safely, which gives us some clues about the chemistry involved, because acids that contain fluorine are usually glass etchants. Also, because the creatures can grow in nearly any environment, no rare or exotic elements are involved. I'm no chemist, but I'm guessing a substance called "carborane superacid" H(CHB11Cl11)—one million times more corrosive than battery acid!—would do the trick. (I'll note in passing that there must be a lot of silica, SiO2, in the xenomorph bodies to contain such a chemical monster.)

But as with everything else in AvP:R, the behavior of this acid is inconsistent, and in direct conflict with what we know from previous movies. Sigh! It may be a feeble hope, but I keep daydreaming that someday a lonely Fox executive will, in a fit of temporary insanity, authorize a project called Actual Aliens vs. Actual Predator. Until then, my advice is to skip this movie and save your money for comic books.

Sources:
The Internet Movie Database (www.imdb.com): "Alien vs. Predator: Requiem"
Wikipedia (en.wikipedia.org): "Alien vs. Predator Series," "Gunnison, Colorado," "Lamarckism," "Carborane"
Lonely Planet World Guide, 2007 Edition: Los Angeles—When to Go
2007 Colorado Big Game Hunting Season Dates: www.coloradowilderness.com/seasons.html
Encyclopedia Britannica 2008 Ultimate Reference Suite: "Lamarck"