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Lizard Vision
UCSC Professor Barry Sinervo can tell you everything you always wanted to know about lizard sex, but were afraid to ask--and why it matters to the human race
By Mike Connor
Once, while hiking up in Big Basin, a tiny, colorful lizard crossed my path. Believing it to be a forest's welcome, I reached out and gave it a stroke. Luckily, it didn't cross my mushroom-riddled mind to lick it--I later found out it was a poisonous newt.
"If you'd have licked your finger," says UCSC professor of biology Barry Sinervo, "you might have actually knocked yourself out. The neurotoxin in its skin is the same as a puffer fish."
Ideally, I'd keep Sinervo in my backpack from now on, not just to warn me of toxic newts, but also to help me find the natural wonders of the California coast. Like the Pacific giant salamander --at over a foot long, these slimy beasts are the largest terrestrial salamander in the world. Being one of those people who always seem to glance out the car window at the exact moment when a dog starts to poop, I figure I can use Sinervo's good luck to glimpse something more profound.
Like lizards totally going at it.
It turns out Sinervo is well-versed in the ways of lizard love, having witnessed more lizard sex than anyone you know. Sporting diamond studs in his ears and a tousled mop of hair on his head, the man looks more like an outdoorsy rock star than a professor. As a career herpetologist (one who studies reptiles and amphibians), he's living out his childhood fascination for reptiles.
"I had two Caimens--it's a small South American alligator--in the upstairs bathtub," recalls Sinervo, who is probably good at hockey because he grew up in Canada. "I had iguanas and newts, and for a long time I had snakes, but my wife put a stop to that because they were getting out too much. Then my grad school buddy told me you can work on lizards for a Ph.D. and get a job catching lizards. It's every 10-year-old's dream job."
In his upcoming lecture for the Santa Cruz Museum of Natural History on Feb. 4, titled Sex in Lizard-land--Lessons From the Hollister Hills, Sinervo will discuss his studies of the mating habits of the side-blotched lizards of the Coast Range of California, the games of survival they play and what his results can teach us about European cuisine.
Or, as Sinervo puts it, "I'll talk about wine, cheese and lizards."
See, because any naturalist worth their student loans can whip out parallels between humans and animals. It's their bread and butter, after all, to entertain us layfolk with factoids about slug and dolphin sex, or male lizards having bi-lobed reproductive organs called hemipenes, and to make grown men cringe with brutal stories about female praying mantises that bite off their mates' heads.
But Sinervo's work with lizards in California and Europe is leading him to draw some fascinating parallels between the speciation (the division of one species into two or more) he's observed and the cultural factors that contribute to European nationalism. During the course of his research in Europe, Sinervo realized that some of the different "borders" between competing species of lizards coincided with the cultural borders of the Europeans, and sometimes even roughly matched sociopolitical borders.
Many would agree that the last thing we need in this world is a snooty French lizard with excessive pride in the cheese unique to its region, or Italian lizards that refuse to drink wine not made in Tuscany. But what Sinervo's studies really show is that humans are not so unlike the lizards, in that our cultural prejudices also develop along sociogeographic lines.
A Matter of Taste
As I approach Sinervo's lab in the UCSC Earth & Marine Sciences building, two grad students enter before me, carrying huge trays of salamanders. I think they might be candy lizards, but Sinervo tells me they're made of colored wax. They're part of an experiment that will help his students understand what colors protect the Ensatina salamanders, which have evolved to look exactly like poisonous newts. Being made of wax, the fake salamanders will bear the markings of any bird attacks.
"We think that when we put those suckers out, they won't get bitten by birds," says Sinervo. "It's like forensic science; these are going to be the victims, the 'clones' that are going to be attacked. But the beauty is that these don't get harmed and we can study natural selection in action, which is what I specialize in."
With funding from the National Science Foundation, Sinervo is even learning about the way birds see their prey (they can see in the ultraviolet), and how they might have evolved to avoid the brightly colored newts and the copycat salamanders.
"Natural selection will teach the birds a lesson," says Sinervo. "And when they eat the newts, they're probably distasteful, which is a really potent form of learning. Even humans--if you go to a restaurant and end up getting food poisoning, what's the likelihood that you're going to go back? None. And that's why these salamanders can cheat; they can wear the colors without the toxin. They're evolutionary cheaters."
Of course, in the game of survival, cheating isn't against the rules. Salamanders use whatever defenses they can to survive, whether it be mimicking poisonous newts or blending into the background with camouflage markings. Depending on the region in which you find them, Ensatina salamanders have developed color schemes that help them survive using either the mimicry or cryptic strategies. Along the borderlines, Sinervo says the salamanders won't interbreed because the hybrids end up with markings that don't quite suit either strategy. An optimist might say they're getting the best of both worlds, but a naturalist would say they're getting eaten. Via natural selection, then, the salamanders develop a sort of xenophobia that keeps them mating only with salamanders of identical color.
"Those little changes get built up into bigger changes that cause them to evolve into a new subspecies," says Sinervo, "in which case selection is determined by a predator and not who you're involved with in your own local population."
Rock-Paper-Scissors
But while the Ensatina salamanders are living out their evolutionarily segregated lives, three differently colored male side-blotched lizards in the sandstone region near Los Banos are engaged in a competitive game of "rock-paper-scissors" among themselves. With three different throat colors--orange, yellow and blue--each morph has its strengths and weaknesses that help it survive. Says Sinervo, "It's pretty wild because they're locked in a genetic cycle that's not really good for the species, but they can't escape it."
In order to understand the game, a little bit of characterization is necessary:
Orange Throats (Big Bullies): They're territorial loners full of testosterone that makes them bigger and more aggressive than the other morphs. Says Sinervo, "They're like body builders, because they can literally beat the snot out of the other types."
Yellow Throats (Sneakers): Much smaller in size, they can nevertheless outsmart the orange throats by pretending to be female. When the orange males approach, they give the female rejection display, which Sinervo describes as "this intense head vibration, and then they arch their back and look really pissed off." The orange males fall for it. Meanwhile, the yellow throats are copulating with the real females like crazy, right under the orange males' noses.
Blue Throats (Gang-Bangers): Without superior size or cunning, the blue throat males have nevertheless developed a strategy that allows them to kick some ass: cooperation. Not so easily fooled by the yellow throats' reindeer games, they gang up on them and drive them away, after which the blue throats are free to wine and dine the females at their leisure ... or at least until the big orange throats come back into the picture.
The result is this: When the big orange males are plentiful, they handily cock-block the blues, but meanwhile get cuckolded like crazy by the yellows. A generation or two later, when the big orange population wanes and the wimpy yet clever yellow throats become plentiful, the blues have little trouble ganging up on and driving away the yellow throats to gain access to the females. And then when the blues become plentiful, the big oranges step in with their manly muscles again, and the cycle repeats.
Sinervo says that this is the only example of the rock-paper-scissors game that scientists have observed in nature, with the most interesting part being the cooperative behavior of the blue males that Sinervo attributes to their genetic makeup.
"They cooperate with each other, which is actually really astonishing in the animal kingdom," says Sinervo. "The blue [gene] makes them search for other blue males, and then they cooperate. It's really interesting from the point of view of animal scientists, because people have been looking for such genes for a long time."
Sinervo's rock-paper-scissor model simplifies the social dynamics so that a child can understand them, but he also thinks it embodies very fundamental social strategies in humans as well.
"Either you usurp, cooperate or you cheat--these are the three ways of making it socially, and they're really fundamental," says Sinervo, "and the models that we've developed probably apply to humans as well. Competition, altruism and cheating usually evolve in concert with a very simple thing: a tag. With lizards, it's the colors. With humans, we have linguistic tags, cultural tags like the kind of food we eat, and also religious tags. The model would predict that you're more likely to cooperate if you share the same culture and religion. And the flip side is also true-you're more likely to rip each other apart in war if you have cultures on two different sides of the barriers. But here's where it's important to make a distinction in the models. In lizards, it's all genetic. Humans can evolve in two ways: culture can evolve, which is passed on as ideas and language. Anybody can pick up a language, it just depends on how good you are at assimilating yourself. With cultural evolution, there aren't really strong differences, but nevertheless they can evolve into genetic differences over time. We can see genetic markers on some language borders, because they've been separated for long enough that genetic differences have built up.
Consider the Lizards
The Tree of Knowledge is fruitful, and as Sinervo can tell you, the Animal Kingdom is still a ripe source of insight into the human condition--and not just because it helps us to discover which brand of eyeliner is the least toxic. From Socrates to Jesus to Newton to Hegel to Thoreau, philosophers have long sought wisdom of and through nature. But anyone who's ever zoned out on National Geographic Explorer can attest to the brutal satisfaction of watching Darwin's unflinching theory of natural selection at work.
The secular implications of his seminal work The Origin of the Species rocked the world in 1859 like a hurricane, and still cause controversy to this day. As recently as 1988, at least one Sunday School teacher drew a fish with feet on it and then crossed it out, explaining that God created everything as we see it. Little did he know his little drawing would end up adorning the bumpers of countless nonbelievers.
More than just spiteful little barbs against Christianity, those little markers attest to the compelling story of natural history and what it reveals about humanity.
Jesus of Nazareth knew the power of nature metaphors, using parables to illustrate the ways of God and man to a population composed largely of farmers. In his conciliatory chill-the-fuck-out speech to the clothes-strapped poor, he asked the people to consider the lilies of the field, that "toil not, neither do they spin. And yet ... even Solomon in all his glory was not arrayed like one of these. Wherefore, if God so clothe the grass of the field ... shall he not much more clothe you, O ye of little faith?"
Though this comparison is questionably vague (Are we supposed to be the grass or the lilies? And are lilies stylish, or even efficient insulators?), it at least appears to suit its agriculturally dependent audience--which is much more than can be said about those same words here and now. A similar sermon delivered by a politician today would only piss off an impoverished constituency, because who the hell wants to be among the blessed meek who turn the other cheek in the land of milk and honey? Many social reformers would agree with John Cleese, who, as a member of the People's Front of Judea in Monty Python's The Life of Brian, scoffed that "what Jesus blatantly fails to appreciate is that it's the meek who are the problem."
Cleese's quip wryly echoes a sentiment common to all revolutionary populists trying to undo the rule of their usurpers. Jesus' pacifist message lacked the cooperative "power to the people" sensibility that would eventually lead to the democratic organization of society. In his book The End of History, Fukuyama argues that the liberal democracy may be "the endpoint of mankind's ideological evolution" and "the final form of human government," taking cues from the German philosopher Hegel.
Writes Fukuyama: "Hegel believed that the 'contradiction' inherent in the relationship of lordship and bondage was finally overcome as a result of the French and, one would have to add, American revolutions. These democratic revolutions abolished the distinction between master and slave by making the former slaves their own masters and by establishing the principles of popular sovereignty and the rule of law. The inherently unequal recognition of masters and slaves is replaced by universal and reciprocal recognition, where every citizen recognizes the dignity and humanity of every other citizen, and where that dignity is recognized in turn by the state through the granting of rights."
Of course it would be ridiculous to argue that the Bush Administration is merely accelerating this historical endgame by spreading our beloved "liberal democracy" to the Middle East, Mars and beyond. Dignity and humanity are still trampled upon every day as we continue to compete, cooperate and cheat in our lizard-like games of survival.
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