Garter Snakes (also known as grass snakes) are found worldwide expect Antarctica. There are many different species of garter snakes.
Common garter snake (left)-University of Maryland, San Francisco garter snake (right)
They vary in size and colour depending on the areas they are found in. Brown, black, green and sometimes grey, garter snakes usually have a prominent stripe or two, red or yellow, on their sides. They are not poisonous but will bite you if they feel threatened. They range in length from two to three feet. If you pick them up they leave an awful nasty odour on your skin and clothes, however they won’t hurt or bite you. If they did bite you, they have no venom.
Eastern black garter snake (left), Checkered garter snake (right)-photos John O. Hollister
They usually live near ponds, creeks and streams or any other sources of water. They are found in long grass around fences and houses. Be careful if you are trimming these grasses as the sting from the weed whacker can kill snakes. Having one of these guys in your garden is a bonus. Especially if you are a west coast gardener and have a problem with slugs. They love slugs and snails. They are active most of the day but rarely seen in the heat of the day and find somewhere to hide for this period. Although they eat worms, they are still a gardeners friend. Mating occurs in early spring or fall depending on species. Females have up to 40 live babies at one time. Most garter snakes hibernate during the winter. The hibernators band together in large groups and emerge again in the spring.
Two striped garter snake (left)-San Diego Natural History Museum, Mass of snakes (right)-Nature Photos Manitoba, Canada
All of these snakes eat slugs, snails, small insects, small frogs, toads, worms, leeches, mosquito larvae and small fishes. The snakes in turn are eaten by birds, wild dogs, cats and occasionally rodents.
How to Attract Them to your Garden
Snakes like heat so a good idea is to mound up some dirt and soak it thoroughly. Cover this with a black plastic garbage bag secure to the ground with dirt or stones. This makes a humid environment for the snakes and they will stay. I would advise making this around your garden since snakes will eat lots of bugs. They can be seen basking in the sun near the shelters they approve.