Written by Maria MacRae
Photograph by Ken Hunt

Common Garter Snake
Thamnophis sirtalis

Found across Canada, from the Pacific to the Atlantic coasts, the common garter snake is the most widely distributed North American snake. They are called garter snakes because of the patterning on their sides, which resembles that of garters once worn by men to hold up their socks.

Garter snakes range in length from 60 to 80 cm, while some have reached lengths of over 135 cm. Their colour varies greatly, from green or grey to almost black, but they usually have noticeable side and back stripes. Several subspecies have been defined, although even within these subspecies there is colour variability.

The patterning of the garter snake allows it to blend into its surroundings, which is generally quite varied and irregularly coloured. The striping makes it less visible when moving through the vegetation - the continuous line belying its movement.

Some snakes bear live, fully formed young, while other snakes lay eggs that later hatch. Garter snakes give birth to live young in late summer. Although one litter was recorded at 98 babies, most garter snakes give birth to between 20 and 40 babies per litter.

Despite their harmless nature, many people fear garter snakes. And yet these docile creatures play an important role in your garden's ecosystem - they eat earthworms, frogs, and mice, among other things. In turn, they provide an important food source for many birds and mammals. The red-shouldered hawk, in particular, relies on the collection of snakes to help feed their young during the nesting season.

A garter snake's first instinct when faced with an oncoming predator, such as man, is to hide. Most times you won't even know that there are snakes around. If backed into a corner, many snakes will try to bluff their way out through a show of temper. It is only once picked up that garter snakes will attempt to bite. They will also release a foul-smelling musky liquid as a form of defence.

Contrary to common belief, snakes are not slimy. As a reptile, snakes have a protective outer layer of scales, which are made from the same material as our fingernails - keratin. It is amphibians, such as frogs, that have a "slimy" feel.

Garter snakes have adapted to a variety of habitats - forests, streams, fields, wetlands, and even urban areas. To make them feel at home in your garden offer areas of dense foliage close to the ground. This provides them with safe areas for feeding and shelter. Piles of logs or leaves are other appealing hiding spots for snakes.

Be sure to add a rock pile or rock wall near sheltered areas. Snakes are cold-blooded, which means they are dependent on outside sources of heat to warm their bodies. A warm rock in the sun is a great place for them to soak up some heat.

In the winter snakes hibernate. Incapable of long migrations, snakes must find a suitable hibernaculum in the vicinity of their summer haunts. They require a secure den with a low temperature that remains above freezing. Because they are susceptible to loss of body water, their hibernation site must also be close to the water table (but not flooded). A lack of adequate hibernacula is a limiting factor in the success of snake populations. You can help local snakes by building your own snake hibernaculum.

Some interesting snake facts:

• Snakes can't crawl backwards - they can only turn the front half of their body and start moving in the opposite direction
  
• Despite a lack of external ears, snakes can hear. Sound waves are transmitted from the skin on the side of their skull to the jaw muscle to their ear bone.
  
• A snake's sense of smell is of critical importance. Snakes use their tongues to augment their ability to sense smells. Odour particles adhere to the tip of their tongue and are transferred to the roof of their mouth and then delivered to a special chamber for sensing smells. This is why they often flick their tongues in and out.