Q How many species of snakes are there?

— Erin Clawson, Sun Prairie, Wis.

A Dr. Christoph Mans, exotic animal specialist at the University of Wisconsin-Madison’s Veterinary Care Hospital:

There are more than 3,400 snake species worldwide, and they exist on every continent except Antarctica. There are about 50 snake species in the United States. Some are venomous, such as the timber rattlesnake and the massasauga rattlesnake.

Other snakes, such as the corn snake, are friendly and can make excellent pets for people who like to keep snakes. The corn snake can get up to 6 feet in length and is native to the southeast and central United States.

Snake anatomy and diet vary tremendously based on the habitat. There are big constrictor snakes such as the anaconda from South America or venomous snakes like cobras or mambas. Some have more fangs than others.

Many snakes eat rodents or bigger mammals, but some snakes, such as garter snakes, only eat fish or amphibians.

While body size, jaw anatomy and diet vary across snake species, several characteristics are similar to all snakes.

Snake skin is very dry and smooth, and snakes will shed their skin several times a year. The whole skin should come off in one layer, and underneath you have a new skin layer.

Snakes use their tongue in order to smell better. They take little smell molecules and put it against an organ in their nose so they have a better idea of their environment.

So every time you see a snake tongue flicking, it’s trying to smell its environment.

Like all reptiles, snakes are cold-blooded animals, meaning they don’t produce their own body heat. They need heat from their environment to increase their body temperature and be active. That’s why snakes are inactive in the winter cold and more active in the warm summer.

Blue Sky Science is a collaboration of the Wisconsin State Journal and the Morgridge Institute for Research.