GARTER SNAKE

 

TAKEN SUMMER 2013 AT THE POND WEST OF THE TRAIL
TAKEN SUMMER 2013 AT THE POND WEST OF THE TRAIL


Garter snakes (Thamnophis) are very common throughout North America. They range from southern Alaska and Canada to Central America. It’s one of the northernmost snake species in the world.  The garter snake is so successful because of its ability to adapt to many environments and food supplies. The western varieties are more aquatic than the eastern ones.

WHY GARTER SNAKES ARE CALLED THAT
WHY GARTER SNAKES ARE CALLED THAT

Garter snakes are carnivorous and will eat about anything they can overpower. Those inhabiting dry land eat slugs, lizards, rodents, insects, and ants. The more aquatic snakes eat fish, tadpoles, frogs, leeches, toads, salamanders, frog eggs, and minnows.

When captured garter snakes may coil and strike, but typically they will go into a defensive mode with their head beneath their body and the tail twitching to attract the attack. They will try to become unpalatable by secreting a musky smell near their cloaca and feces. Although garter snakes are not considered harmful to people they do produce a mild neurotoxin that helps overcome their prey. They have a pair of hooked teeth at the back of their jaws for grasping prey, but no teeth for injecting venom or chewing. They swallow prey whole.

Garter snakes communicate with phermones. Females secrete a phermone that immediately attracts males at mating time. Males on some occasions secrete both male and female phermones. Since mating happens soon after the snakes emerge from bromation — a reptilian low metabolism state similar to hibernation — a male may steal body heat from other males when they attempt to copulate with him because he smells like a female. Indeed, copulation is a group event among garter snakes. One female my be surrounded by as many as 25 males with mating fever in what is appropriately called a “mating ball.”

See THE WORLD LARGEST GATHERING OF SNAKES

Before garter snakes enter brumation they stop eating for two weeks to clear any undigested food. Brumation is triggered by low temperatures and lasts until the environment warms up. Mating starts immediately after brumation ends. After mating the females leave the den to find food. They may store sperm for up to three years! Gestation takes about three months;  as few and three and as many as 80 young are born live. They are independent from birth.

The Oregon Department of Fish and Wildlife lists four sub-species of garter snake:

  • Pacific Coast Aquatic Garter Snake (lives near water  such as riparian areas of rivers, ponds, streams, and wetlands)
  • Western Terrestrial Garter Snake (found in a large variety of habitats often far from water. Sometimes called the “wandering” garter snake)
  • Northwestern Garter Snake (lives in wooded areas of the Willamette Valley, suburbs and parks. Lives mainly on slugs and worms)
  • Common Garter Snake (wide range of habitats and prey)

Garter snakes are also food for other animals. The video below is one my wife and I took while on the Fanno Creek Park trail in Beaverton. It shows a Great Blue Heron eating two garter snakes in the space of about 45 minutes.

ADDED 8/13/2014

GARTER SNAKE STUFFED WITH MICE; IMAGE BY LOON ISLAND OUTDOORS, ONT, CAN
GARTER SNAKE STUFFED WITH MICE; IMAGE BY LOON ISLAND OUTDOORS, ONT, CAN

LINKS ABOUT GARTER SNAKES

 

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5 thoughts on “GARTER SNAKE”

  1. Well, I am glad to learn garter snakes eat slugs, ants, insects, rodents and lizards. I am totally unnerved though that up to 80 snakes may be born at one time! The most interesting fact was that males fast for 2 weeks prior to “doing it”. What’s up with that?!

    1. That’s a very good question. It has led me to review the article where I read about brumation, and it turns out I misinterpreted the sequence of things that happen when snakes brumate. Brumation is a state of lowered metabolism and inactivity that reptiles enter into when temperatures drop. Since reptiles do not generate body heat they drop down in temperature with the ambient temperature. It’s a time when they need to conserve energy to survive.

      In the case of garter snakes it is important that they eliminate any undigested food because it takes energy to digest food and undigested food might rot in their digestive system while they’re inactive. That would be fatal. So they stop eating a couple of weeks before they go into brumation.

      This is somewhat different from hibernation, the lowered metabolic state of mammals such as rodents and bears during winter. Mammals pig-out to build body fat before hibernation. They really conk out and live on fat reserves. In contrast, reptiles just become very inactive. A few days warmth can bring garter snakes back to an active state.

      Evidently garter snakes come out of brumation horny (and who can really blame them?). Both males and females are ready to mate with vigor. Then they go have lunch

      I’m going to revise my page on garter snakes.

      1. Hilarious! I once led a group of teenage drug addicts on a nature hike through Tryon Creek State Natural Area, close to where I live. When we came across a banana slug, I began to do my usual performance routine with the slug, which young and old audiences always enjoy. And then one of these hardened teens asked me .. well, how do slugs, y’know, do it? Well, having seen the Nature (or BBC, I forget) video on this hot topic, I launched it …. (after telling them that I couldn’t ever get into this with elementary school kids …) …. And let me assure you .. the mating habits of snakes are positively prosaic compared to that of the banana slug…:-))) I had a dozen teenage, otherwise apathetic, addicts in a state of rapt attention. T’was a teachable moment never to be forgotten….. See ya … ~roland begin

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