Red-sided Garter Snake and Eastern Garter Snake
Special Note
There are two different kinds of Common Garter Snake in Manitoba. They are the same species, but are considered to be different types. The Red-sided Garter Snake is the most common in Manitoba while the Eastern Garter Snake is found only in the southeast of the province. Their habits and life cycles are the same so this page gives the information for the Red-sided Garter Snake and just gives the differences in the way the two kinds look.
What it looks like
Red-sided Garter Snakes are medium sized snakes. They can grow to be over 110 cm long, but most are 40 to 70 cm long. They are dark olive to black in colour with yellow lines down their sides and along the middle of the back. Eastern Garter Snakes are lighter in colour and have wider yellow lines.
More PicturesLook-alikes
All three kinds of garter snakes found in Manitoba can be hard to tell apart. The way to tell a Plains Garter Snake from the other two is to look at the yellow line on the sides. If the line is in the 3rd and 4th rows of scales up from the belly it is a Plains Garter Snake. If the line is in the 2nd and 3rd rows of scales rows it is either a Red-sided Garter Snake or an Eastern Garter Snake. Red-sided Garter Snakes will usually have red spots on their sides. Eastern Garter Snakes don't have red spots and have wider yellow lines on their sides.
Name
Garter snakes look like "garters" which are striped bands used to hold up socks. Red-sided Garter Snakes usually have red spots on their sides. The Eastern Garter Snake is found mainly in eastern Canada.
Scientific Name
The Red-sided Garter Snake's scientific name is Thamnophis sirtalis parietalis. The Eastern Garter Snake's scientific name is Thamnophis sirtalis sirtalis. Learn what these mean on this page: Scientific Names.
Where it lives
Red-sided Garter Snakes are found throughout central and western North America mainly in forest habitats. In Manitoba they are found in the southern two thirds of the province. Eastern Garter Snakes live in forested habitats in eastern North America and only live in the very southeast corner of Manitoba.
Where Red-sided Garter Snakes live in North America.
Habits
Both garter snakes live in forested areas and hunt during the day, usually near wetlands. They stay hidden at night or during cold weather. They spend winter below the frost line in caves, animal burrows or alongside building basements. Red-sided Garter Snakes spend winter in very large groups in limestone caves in Manitoba. Once mating is over they move away from the dens to hunt near wetlands all summer.
Food Web
All our garter snakes feed mainly on amphibians, especially frogs and toads, but they will eat salamanders, too. They eat worms, small fish and other soft-bodied animals like slugs and tadpoles.
Garter snakes are eaten by birds such as hawks, owls, herons and cranes and by mammals like raccoons, skunks, weasels and bobcats.
Life Cycle
Red-sided Garter Snakes mate in spring when they leave their winter dens. Males wait by the den for females to come out so they can mate with them. Females give birth to live young from late July to September. A large female may give birth to more than 50 young. The baby snakes are about 12 - 15 cm long at birth. It takes them 2 or 3 years to reach adult size. They may live for 5 - 8 years.
Numbers
Red-sided Garter Snakes are very common in Manitoba. In summer when they are out feeding there may be 2 - 5 snakes per hectare. At large winter dens in Manitoba's Interlake region there can be 5,000 - 10,000 snakes in a single den! In spring when they emerge there can be thousands of male snakes near the den at one time.
That's a lot of snakes! Male Red-sided Garter Snakes waiting for females!
Eastern Garter Snakes are common in a very small region of southeastern Manitoba.
Special Things
Red-sided Garter Snakes form the largest groups of reptiles found together at one time on earth! There can be more than 10,000 emerging together from a single den.
All garter snakes protect them selves by pooping out a smelly musk if they are attacked, or if a person tries to pick them up!
How to Find Red-sided Garter Snakes
Like all snakes the best way to find them is to look for them basking along trails or roads. In Manitoba you can visit the Narcisse Snake Dens to see thousands of snakes during their spring emergence. The middle of May is usually when the most snakes can be seen.
Use by People
People used to be allowed to collect Red-sided Garter Snakes at their dens to sell for scientific studies or dissections. Now the snakes are protected and people can enjoy seeing them. Some people try to keep one as a pet, but they should not be taken from the wild.
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For more on Red-sided Garter Snakes in NatureNorth.com follow these links:
Snakes Alive! | Narcisse Snake Dens | Garter Snakes in the Classroom
