A slithering carpet of 75,000 snakes in a space the size of a living room. It’s hard to imagine wanting to get close to such a scene, but every year it happens, and
visitors from around the world attend the unusual reptilian display in the remote hamlet of Narcisse in Manitoba, Canada.
The peak of the “emergence,” as the province’s
website calls the unusual event, is expected this weekend. Over the past week and a half, guests to the wildlife area have had hints of what’s to come. Thousands of
red-sided garter snakes have gradually awakened from an eight-month nap in their subterranean limestone lairs. They tumble about the craggy landscape in tangled knots with a singular focus: reproduction.
Over the winter, snakes seek shelter from below-freezing temperatures in limestone caverns in Manitoba’s
Interlake region. They survive on stored fat, and when the weather gets warm, as it is now, they surface.
“When they wake up literally after eight months underground, I don’t know about you, but I’d want to get a Big Mac or a meal,” said
Bob Mason, a reproductive biologist at Oregon State University who studies these snakes. But the first thing on the snake’s agenda is sex.
The males pour out of the dens first and wait for the females to slowly trickle out over the course of a few weeks.
“Once she gets up off the floor, she’s sort of swarmed by all of them,” said Doug Collicutt, a local biologist.
In this sea of snakes, a female isn’t easy to find, even though she’s three to four times bigger. At times, the ratio of males to females is 10,000 to 1. “Imagine trying to find a slightly bigger piece of spaghetti in a colander of spaghetti, and it’s moving,” Dr. Mason said. So the snakes use scent.
A female secretes pheromones from her skin, luring dozens to hundreds of males that try to court her by rubbing their chins along her back and flicking their tongues. She ultimately decides when she is ready to mate by a mysterious mechanism called
cryptic female choice.
The closest male wins and leaves a stinky plug inside her that tells others to back off. She can wait a couple days for the plug to dissolve and mate with another snake, or she can slither off into the swamps to feed and give live birth to her babies in August. (In case you’re wondering, the female can store sperm until she’s healthy enough to reproduce, said Dr. Mason, who documented a female snake who gave birth seven years after mating.)
By June, there are no snakes at the dens, but they all return in September — except the babies. Of the 250,000 snakes born each summer, not one can be found in the den that fall. For centuries, some thought they stuck out the winter in giant ant hills, but Dr. Mason believes the creatures freeze and come back to life like
wood frogs. He has no evidence, but said he hoped to prove himself right before he retires.
