Garter Snake Hibernation

Article by Kate Bradley, Charlotte Cherkewski, and Rajika Robinson,

Mrs. Cohen’s Grade 6 Area Enrichment Class, Northlake Woods Public School

Winter is a tough time for garter snakes, food is scarce and the air is cold. Their only option: hibernation. Each year, garter snakes hibernate in various dens during the winter to keep warm and alive.

Cold Alert

Before any snake goes under, they have to stock up on food and body fat to survive the long winter months. Come October, garter snakes in the lower half of Canada will go back to their dens – holes in the ground or under rocks – and come out again late April. The dens, also called hibernaculums, may even be the same place they hibernated from previous winters. The cold air is an easy sign that the snakes have to start getting ready for the cold months ahead. To get ready, they burrow into their dens. These dens can hold hundreds of snakes, all trying to stay warm. They have no need to eat or sleep because they came prepared. But eventually the snakes no longer have to try and stay warm, spring is here! The males come out first, but no snake comes out quickly. It can take over two weeks for the snakes to come out. Freedom at last!


This process helps garter snakes all over Canada to survive during the frigid winter months, keeping them warm and safe. Slithering into dens mid-October keeps the snakes from having to migrate south to survive. If the garter snakes donʼt stay warm enough, they could die, and the next generation of snakes will not be born. If the snakes come out of their dens too early, then an early frost might kill them. Sadly, an early frost is not the only thing that might kill them. If the snakes den is not below the frost line (deep enough underground), they could freeze to death while still in their den! Another unfortunate way they can freeze, is when the same den the snakes use- that has been safe for years- suddenly turns lethally cold in an unusually freezing winter. If the garter snakes dodge all of these common catastrophes, they might live to see the next winter. Congratulations to the survivors!

Fun Facts

  • Other animals, such as bears, hibernate as well but not the way reptiles do. Mammals sleep the whole winter, and live off fat reserves whereas reptiles are alert and-if itʼs cold enough- donʼt even lose weight.
  • For such a small snake, they lay a lot of eggs. The most snake babies born at one time was 98!!
  • If it is really cold out, the snakes digestive system temporarily shuts down so if they ate something it would just sit in their stomach and rot, and that in turn could kill the snake.
  • A garter snakeʼs bite contains neurotoxic venom that cannot kill, but only slow down itʼs preyʼs movement.
  • How did the garter snakeʼs name come to be? Well, the snakes were compared to the garters men wore to hold up their stockings, many years ago.
  • When they first hatch, they are 12.5 to 23 cm long and can grow from around 50 to 140 cm long.
  • Sometimes, only two-thirds or half of the number of snakes that go into hibernation come back out in the Spring.
  • Their scientific name is Thamnophis sirtalis.
  • Garter snakes are important because they eat harmful insects in and around your garden.