One way to determine the sex is to study their behaviour. In spring, male snakes gather in large numbers at the surface of the den waiting for a chance to mate with a female snake. As each female emerges from her winter den she is vigorously pursued by a band of males who entwine themselves around her to form a mating ball.

The one female is usually at the centre and lead of the mating ball as it slithers like a tangled matt of spaghetti along the ground or up a shrub. In addition to physical differences between the two sexes in the vent area, adult females are larger than adult males both in length and body thickness.

Snakes, like all other kinds of wildlife, need food, water and shelter to survive and produce young. While food and water are plentiful in Manitoba's Interlake region, and other parts of the province, it's the availability of winter dens in limestone bedrock that make this area an ideal home for red-sided garter snakes. It's only by amassing below the frost line that snakes are able to survive Manitoba winters. The dens themselves, a network of crevasses and caverns extending to the earth's surface, were formed by underground water that eroded and collapsed the limestone.

In their first winter most juvenile snakes remain where they spent the summer - seeking refuge in ant hills, animal burrows or any crevasse that will take them below frozen ground. It's only during their second year that they migrate to an established den site and continue to use it year after year. Although most adult snakes seem to use the same den site, marking and recapture studies have shown that some snakes use alternate dens. It is believed that snakes home to den sites using scent trails.