by Janice Welsh
Photographs by Barney Oldfield
Snakes are amazing. They have no legs, but they can move around quickly. They have no arms, but most can climb trees, and some can squeeze small animals hard enough to stop their breathing. They smell with their tongue. And they can swallow things that are fatter than they are.
Like turtles, lizards, crocodiles, and alligators, snakes are reptiles. They are the only legless reptiles in Minnesota. Perhaps because snakes seem strange, some people are afraid of them. But snakes are remarkable too. This story tells about the 17 species of snakes that live in Minnesota.
The illustration above shows how a snake sees, hears, smells, and touches.
Clear scales called spectacles cover the eyes. A snake has no eyelids, so it can't close its eyes. It can only see things up close.
When a snake flicks its forked tongue, each fork picks up chemicals from the air. The snake puts one fork in each of two holes in the roof of its mouth.This is how it sends a smell signal to its brain.
A snake does not have ears. Its skull and jaw bones pick up vibrations. A snake can feel a soft touch on its skin of dry scales.
Sharp teeth slant back to hook and hold a small animal. The snake swallows the animal whole.
Chasing fast mice and other rodents can be a problem when you do not see well. Massasaugas and timber rattlesnakes have a special tool to help them find warm-blooded animals - pits between each eye and nostril can detect the animal's body heat.
A snake has between 200 and 400 bones in its back, each with a pair of ribs. (You have about 33 bones in your back and 12 pairs of ribs.) Because the snake has so many bones, it can easily bend and glide.
You can find common garter, plains garter, redbelly, and smooth green snakes almost anywhere in Minnesota.The southern third of the state has all 17 of Minnesota's species.
Snakes live in all kinds of habitat. You might see a snake in the hills, down by the river, or in the grass in your back yard.
During the cold winter months, you won't find snakes above ground. Because snakes are cold-blooded animals, their body temperature warms and cools with outside air. To keep from freezing, snakes look for a place to hibernate below the frost line. They look for a rock crevice, an ant mound, or a tunnel made by a burrowing animal. The winter den is called a hibernaculum. Generations of snakes return to the same hibernaculum year after year.
Wildlife managers are especially concerned about several species of Minnesota snakes because our state has fewer of them than it once had. Why is that? People have plowed up land for farms and built homes, shopping malls, factories, and roads in many places where snakes once lived. Now snakes have fewer places to feed, nest, and hibernate.
Most Minnesota snakes mate in April or May after they come out of hibernation. In early summer, females of most species lay long, white leathery eggs in hollow logs or in loose soil. The young hatch in August and September. A baby snake looks like a miniature adult snake.
Some Minnesota snakes, like garter snakes and rattlesnakes, give birth to live young. The baby snakes are born in August or September.
Baby snakes live on their own after they are born or hatch. More than half of young snakes die before they are 1 year old.
Following photos by Barney Oldfield.
Snakes are carnivorous. Different snakes have different ways to catch and eat their prey. A bullsnake is a constrictor. It coils around its prey, usually a rodent, and squeezes tighter and tighter until the animal suffocates. A rattlesnake is a venomous snake. It uses a poisonous bite to kill its prey, usually gophers and mice. A garter snake simply grabs its prey, usually earthworms, in its mouth and swallows it live.
Because snakes are cold-blooded and do not produce their own body heat, they don't need to eat as often as warm-blooded mammals or birds must. In the wild, snakes might eat only every other week during the summer.
Can you imagine eating a watermelon in one bite? If you were a snake, you could swallow it whole. A snake can swallow an animal that is five times larger than its own head. The snake's lower jaw unhooks from its skull so its mouth can open wide enough to take in the animal.
A toad will puff up to try to make itself too big to swallow. An eastern hognose snake will clamp down its jaws and use its back teeth to try to make the toad pop. If the toads pops, the snake can swallow it whole.
Hawks, herons, egrets, owls, foxes, and other predators hunt for snakes. To keep from being eaten, snakes hide in tall grass and under bushes, logs, and rocks. Snakes also use their speed to get away.
Many species of snakes try to fool you into thinking they are more dangerous than they are. For example, the hognose snake hisses loudly and flattens its ribs on either side of its neck so that it looks bigger. If this act doesn't scare you away, the hognose snake will roll over and play dead and wait for you to leave. The bullsnake coils up, vibrates its tail in imitation of a rattlesnake, and strikes to frighten off a threatening animal. Rattlesnakes have hollow fangs that deliver poison. Venomous snakebites are rare in Minnesota.
How to Be a Friend to Snakes. Here are some things you can do to help snakes:
Janice Welsh, who wrote this story, works for the DNR Nongame Wildlife Program.
A complete copy of the article can be found in the September-October 1994 issue of Minnesota Conservation Volunteer, available at Minnesota public libraries.