Every spring, the Canadian wilds of Manitoba become a sea of nightmarish writhing snakes. A tangled mass of thousands of red-sided garter snakes come together in what is considered the largest snake-gathering in the world. After spending the long winter months in hibernation, they all come out for a bit of a breather, to frolic in the sun and perform their mating rituals.
The fascinating event takes place at the Narcisse Snake Dens, a few kilometers north of Narcisse, in Manitoba province. What makes Narcisse the ultimate rock-concert equivalent of the snake world? Well, the answer to that question dates back to the Paleozoic era, when the area of Manitoba was covered by an ancient ocean. The water doesn't exist anymore, but the ocean bed still does -- layer upon layer of thick limestone rock covers the region, with thousands of natural crevices, tunnels and caves. Rainwater seeps through these cracks and when the rock gives way near the surface, the resulting collapse forms a sinkhole.
The cold-blooded snakes happen to love these sinkholes, which are perfect for hibernation during the harsh Canadian winter with temperatures reaching 50 degrees below zero. So they migrate from far and wide and settle into the sinkholes, putting a good distance between themselves and the frost line. Because there's a limited number of sinkholes, also known as den sites, all the snakes in an area have to go to the nearest den site. So there are literally tens of thousands of snakes crowded into just one sinkhole the size of the average living room.
They stay there all winter, only to slip out of their limestone dwellings in late April/early May, when the snow melts. The males are the first to come out and play; they hang out on the surface of the ground in great, tangled heaps, waiting for the females to arrive. When the females finally do make an appearance, it's really difficult for the males to spot them. That's because from a snake's point of view, the region exactly is like a large sea of spaghetti.
So when they manage to detect a female through her sex pheromones, the males crowd around her in large numbers. Pretty soon it becomes a free-for-all, with as many as fifty males attacking a single female at a time. Together, they form a huge 'mating ball' of snakes, moving and writhing across the ground. The balls are everywhere -- on tree limbs, on plants, on ledges and on the ground.
"Often times, when a group of these courting males all gather around one female, trying to be that lucky guy that's gonna mate with her, they'll get so wrapped up, they can tumble down on a hill literally like a ball. So people call them mating balls," said Bob Mason, Chairperson of the Biology Program at Oregon State University. "Even though there's tremendous competition for mates, males are not fighting with each other, they don't have dominance hierarchies, they don't have territories set up like other animals would do in a similar situation."
The Narcisse Wildlife Management Area has four active snake dens, all connected to each other by a three-kilometer self-guiding interpretive trail. According to Professor Mason, each pit has around 35,000 snakes and the general area is an 'ocean' of over 250,000 snakes. At one point, the population of red-sided garter snakes in Narcisse was nearly double of what it is today. But terrible weather conditions in 1999 killed several thousands before they could reach their den sites.
One of the reasons they couldn't make it on time was because their migratory path cuts right across Highway 17. Many snakes were either crushed by speeding vehicles or delayed in reaching the den sites. In the past, the vast population of snakes had compensated for these losses, but the winter was unbearably harsh in 1999, causing a significant decrease in population.
To combat the issue, authorities built 15-cm tunnels under the highway, and foot-high snow fences that forced the snakes to use these tunnels. Signs were also put up along the highway, warning motorists to slow down to avoid crushing snakes under their wheels. These measures have worked to some extent -- the number of snake casualties has been reduced to less than 1,000 a year.
The Narcisse Snake Dens are quite popular; every year, tourists and scientists arrive from all over the world to view the spectacular sea of snakes. Observation platforms are built next to the dens specifically for this purpose. The snakes are a big hit with children in particular, because they haven't developed a fear of them, yet. Luke Donaldson, a kid from Beausejour in Manitoba, said: "The garter snakes don't have teeth and they feel cool when you touch them and stuff."
"They don't bite you," added Aiden Donaldson. "They just move around in your hand really fast and stuff."