Early Emergence of the
Red-sided Garter Snake

The following article was submitted to the Alberta Volunteer Amphibian Monitoring Program by a Leduc area naturalist and landowner. She has chosen to remain anonymous.The article details her personal snake-monitoring adventures and field observations.

Since discovering the red-sided garter snake hibernaculum (den) last May 2011, these small creatures have captivated and amazed me. But this spring, on an early hike I was delighted and surprised to see a group of little faces peering out from the hibernaculum entrance. The date was March 28th and the ground was mostly still snow covered, but there they were!

This has found to be the earliest recorded emergence of red-sided garter snakes in Alberta at this latitude (just north of 53o latitude). I watched fascinated over the next few days as these small snakes ventured out. While most would skirt the snowy areas some just went right across the snow or under it!

As the snow gradually retreated with the warmer and longer days, activity around the hibernaculum increased, usually peaking in early afternoon. On days when it snowed, was very cold and/or rainy, there would be little to no activity, with no snakes to be seen or just a very small number present not far from the hibernaculum entrance.

Gradually, snakes would be seen farther away from the hibernaculum. You could often hear them before you saw them as the leaves and grass would rustle as they moved about. At times, large numbers were moving and the whole area seemed alive! While some would slumber in the sun for extended periods, others would be eagerly seeking mating partners. They are amazingly fast moving when motivated!

By early May, activity had slowed considerably around the hibernaculum, although there were still some small active groups. These small snakes have been shown to travel many kilometers from their respective hibernaculum and as they headed off on their journey I could not help but marvel at their adaptability to this challenging climate.

Throughout the summer the hibernaculum area was quiet and I only observed snakes intermittently in the general area. Observing snakes was difficult due to the lush and thick summer vegetation. I suspected that most of the snakes dispersed away from the den area looking for places to forage for their favourite prey and to give birth to their young.

I noticed snakes beginning to return back to the hibernaculum in September, with sightings on September 18th and 20th. Towards the end of September just a handful of snakes were observed at the hibernaculum—some peering out of entrance holes. A couple of others were observed near the hibernaculum at the end of September.

For more about garter snakes from ACA biologist, Kris Kendell, read on!

What is a garter snake?

Garter snakes are small, slender snakes and rank among the most beautiful and most common snakes in the province. Alberta has three species of garter snake—red-sided garter snake (Thamnophis sirtalis), wandering garter snake (Thamnophis elegans) and Plains garter snake (Thamnophis radix). They can all be found in a wide variety of habitats throughout the province, but they are most often encountered along the margins of wetlands, rivers, and other bodies of water.

Biologists and naturalists alike have perceived a decline in garter snake numbers and populations in Alberta, and all three species are considered sensitive to human activities that negatively impact the habitats and food sources in which they depend on. Habitat loss, over-collection, wanton killing, road mortality and destruction of hibernacula (dens) have result in local declines.

The facts about garter snakes:

  • Garter snakes are harmless to people and when approached beat a hasty retreat to dense cover or water.
  • Garter snakes contribute greatly to the environment, consuming insects and small rodents that are often considered pests in urban and agricultural areas, and they themselves are prey to a wide variety of other wildlife species.
  • Garter snakes can travel many kilometres from their winter den to summer feeding and birthing areas.

Winter Survival

Like other reptiles found in Alberta, garter snakes survive the winter in places where they will not freeze. Each fall, Alberta snakes set off from their summer feeding grounds back to traditional winter dens, called hibernacula (singular form: hibernaculum). Hibernacula are often used for many years and hundreds or even thousands of snakes of the same or different species may gather together at a hibernaculum.

Hibernacula include natural subterranean spaces such as the crevices in rocky outcrops, slumps along river valleys and animal burrows as well as human-created sites such as in rock piles, along building foundations, and in cellars. These spaces all extend far underground and below the frost line. The temperatures within hibernacula remain just above freezing and fairly constant because of the insulating effects of the earth.

As snakes enter a period of dormancy they don’t eat a thing for many months and live sparingly off the energy stored in body fat reserves. Eventually, the warmth of spring will penetrate their winter retreats and lure the snakes back to the surface.

Because of the vulnerability of snakes at hibernacula, these communal sites are protected from disturbance under the Alberta Wildlife Act.

How can I help snakes?

As a steward of our natural world, there are many things you can do to help snakes. One of the easiest things is being tolerant of snakes. Some other things you can do include:

  • Conserve the places where snakes live by actively managing and preserving native habitats.
  • Avoid the use of pesticides and poisons that may harm snakes directly or indirectly by affecting their food supply.
  • Keep a careful lookout for snakes on roadways to avoid hitting them.
  • Contribute to a better understanding of the distribution and status of snakes in Alberta by volunteering den and snake sighting information to the Alberta Volunteer Snake Hibernaculum Inventory. For more information contact Kris Kendell toll-free 1-877-777-3764.

Want to know even more about red-sided garter snakes? Read "A Snake Seduction: The mating of red-sided garter snakes" by Dr. Wayne Lynch in Conservation Magazine.