The earth seemed to be writhing and wriggling as more and more snakes emerged from crevices in the limestone. I was frozen to the spot; there seemed no space to take a step without squishing a few.
Red-sided garter snakes are small, slender snakes up to half a meter long, with a couple of parallel stripes running down their length. They are so named because they resemble the elastic bands that held stockings up in the old days. Individually, they are nondescript, but collectively they are a phenomenon. It was spring in Manitoba, Canada, and we were witnessing the emergence of the largest concentration of snakes anywhere in the world. By the end of the first day, I saw squirming snakes even when my eyes were closed.
I remember a scene in an old documentary of a woman briskly sweeping hundreds of garter snakes off her porch. Apparently, people living near the snake dens have to contend with this annual nuisance. We even heard of a couple who mistakenly built their home right atop a den and were over-run with these snakes. After a couple of years of this “nightmare,” the twosome relocated.
The May sun shone brightly but it did little to warm us against the cold wind. I felt like doing little more than lazing in the sun. Yet, here were these cold-blooded animals busily courting and mating. For the last eight months, the snakes had brumated (similar to hibernation) deep underground, and I thought food would be their highest priority. No, being males, they had sex on their little minds. That may be because once they disperse across the countryside looking for frogs and snails, it's harder to find a mate. It's so much easier to hang around the dens and wait for the females to appear. Just like the scene outside some women's colleges.
Invariably, droves of males emerge first while the larger females come out in little groups. When she makes an appearance, several males jump on her, all at the same time, and within seconds she is buried under a mass of wriggling sex-starved maniacs. How's the poor, barely awake, harassed gal to choose a mate amongst the horde? Somehow, she does.
Adding a risqué note to this mating orgy were the transvestites. Males identify females by their scent. Intriguingly, some boy snakes give off an “I-am-a-girl, come-hither” perfume. What possible advantage could they gain by this subterfuge? Did they tire out the competition by sending them into a courtship frenzy and then mate with the females? Or were they just differently oriented?
Two scientists, Rick Shine and Robert Mason, figured that the transvestites did not gain any sexual mileage. When males emerge from the dens, they are cold and slow, but basking in the sun is like offering oneself on a platter to predators. By mimicking females, the cold males are immediately enveloped by warm, amorous males. Not only do transvestites absorb heat from their suitors but by being buried under a pile of them, they are also well-protected from predators. Their first priority is not sex, but getting warm and being safe at the same time.
If transvestism is a survival advantage, doesn't it make sense for all males to act like females? They do. For the first two days after coming out of brumation, every male smells like a female. Once they warm up, they turn straight. Could this shared experience explain why the regular guys let themselves be fooled into protecting their rivals?
Do the transvestites become normal halfway through the courtship, leaving a lot of confused suitors? After examining hundreds of snakes, the scientists found evidence of gay sex. How did they know? After copulation, the male inserts a gelatinous ‘sperm' plug into the female's cloaca to prevent her from mating again. Some transvestites have been found with the tell-all plugs. I can well understand their excuse: it was too cold. And so was I.
