Snakes, Pacific Northwest
Snakes are a large group of animals belonging to the reptile class. Their closest living relatives are the lizards. Together, lizards and snakes form the order Squamata.
They began to appear about 90 million years ago. Scientists believe that snakes are descendants of burrowing lizards that lost their limbs and adapted their vision.
The common garter snake is separated into 3 subspecies in Pacific Northwest, The Puget sound garter snake that lives on Vancouver Island, the valley garter snake that lives in the lower mainland and the red-sided garter snake that lives in the interior and eastern points of the Province.
Adults can reach up to 2 m in length. While markings vary between the subspecies, all the garter snakes in the pacific northwest have a dark grayish green body, a large pointed head and a yellow to greenish yellow stripe down the back. The patterns and color combinations on these snakes can be very beautiful to look at. Except for the melanistic snakes which can be all black.
Common garter snakes spend the winter hibernating in communal dens. They may have to travel a few kilometers to reach a good den site, and these dens often are shared with many other garter snakes, sometimes there can be thousands of them in one den. One den that l saw in Chilliwack must have had tens of thousands in it.
In the spring, males emerge from the den first, followed a short time later by the females. No sooner have the females emerged than the males begin to court them.
Often many males will pursue a single female, the result is a mating ball of snakes, made up of many eager males, and somewhere in the middle of the ball, one single female. The first time I saw this, I was around 5 yrs old and it scared the dickens out of me but now it is an incredible sight to see.
Males are attracted to females by their smell and initiate mating by contact along the length of the female’s body. Once a female has mated, she seals off the opening to her reproductive tract with a plug. This prevents other males from mating with her. Males are able to sense this and usually do not pursue females that already have mated.
Common garter snakes are live-bearing. The young are born sometime in July or August. Females can have up to 75 young or as little as 5 but usually have around 15 young per litter. Biologists value the common garter snake in Canada as these snakes represent some of the northernmost populations of reptiles in the world. Our northern snakes reproduce less frequently and have larger young than their southern counterparts.
This garter snake varies more in color and pattern than any other snake in our region. Sometimes they appear to have blue eyes but this is just a layer of skin over the eye when they are shedding an old skin that makes their eyes look blue, pretty awesome to see.
It is a small snake that can reach up to 60 cm in length, adults are black, brown, or olive in color. They have a stripe running down their back, however, the width of the stripe varies, and sometimes the stripe is missing entirely.
Some individuals have stripes down the sides of the body with spots between the back and side stripes. The colors of these stripes and spots vary like the rainbow to bright yellow, red, tan, blue, white, and cream are the most common colors. While the belly usually is pale, some snakes have bold black or red markings.
Fortunately, there is one marking that is fairly reliable and can be used to help identify the northwestern garter snake, they all have a pale upper lip that is quite visible.
Like the common garter snake and the western terrestrial garter snake, the northwestern garter snake responds to handling by releasing a smelly mix of musk and droppings from its tail vent.
Because of their small size, northwestern garter snakes can be an easy meal for a number of predators such as birds of prey and mink. However, it appears that northwestern garter snakes have learned to make the most of their variable coloration. Studies show that brightly striped snakes flee when faced with a predator. The snake’s stripes make it difficult to tell exactly what direction and speed it is moving. Thus confusing the predator and increasing the chance of escape. While spotted and faintly striped garter snakes use their camouflage and remain motionless to avoid detection from predators.
Northwestern garter snakes are fairly inactive snakes and feed during the day. Their laid back lifestyle works for them just fine because most of the food they eat is even more sedentary than they are. These snakes mostly eat slugs and earthworms, along with the occasional snail and small amphibian. Once an adults mouth is large enough, they will also eat any birds eggs they find.
Northwestern garter snakes are found in southwestern B.C. as far inland as Manning Park and on many of the coastal islands including all of Vancouver Island.
Northwestern garter snakes need two kinds of habitats: summer feeding and breeding areas, and winter dens to hibernate in. They like damp, heavily vegetated areas, including meadows, the edge of forests, estuaries, and beaches. They also can be found in roadside vegetation, in weedy urban areas and around stacked wood and other debris in the yard of most homes.
Snakes can normally be characterized by scaly skin, forked tongue and the ability to swallow prey much larger than their own head by unlocking their jaw. All snakes are carnivorous, although their prey varies.
Garters are one of the most common of snakes found in the Pacific Northwest. They can be found in a variety of habitats. Living up to 10 years in age, they do not grow to any great size, reaching about 1 meter in length. Although throughout the years, l have seen a few big ones.
Garters, due to their small size, are quick to heat up and cool down. Like most reptiles, garters warm up by laying in the sun.
Many of the garters must hibernate during the winter due to the severe drop in temperatures. This period of dormancy stimulates mating behaviors in the spring. Garters hibernate in groups that can contain hundreds, even thousands of snakes, spending the winter together helps keep them warm and provides accessible to each other for spring breeding.
When spring weather arrives, the snakes slowly come awake, some making short forays outside the den, returning for the night to avoid the still cold spring night temperatures above ground.
There is a much rarer snake found on Vancouver Island, the Sharp-Tailed Snake. The Sharp-tailed Snake has a sharp scale on the top of its tail. It is the smallest snake on Vancouver Island, averaging 30 cm in length but can reach lengths of 48 cm. It is reddish-brown to grey. The sharp-tailed snake lays its eggs in the summer and they hatch in the fall. The snake is most active during the rainy months but tends to stay under rocks and other ground covers.