Snake biology

by Tammy McCormack. 0 Comments

Can you believe it is already August and school is just a week away for Frederick County students? Where has the time gone?

It has been one very hot summer. Snake calls have been very slow for the past month. But my busy season is just around the corner and I am looking forward to it.

I get so many emails from you asking all types of questions pertaining to snakes. So I thought this week we would do an overview of basic snake biology.

The body of a snake seems very odd when you first look at it. But the snake has many of the same parts as the human body, including a backbone, heart, stomach, kidneys, and a gallbladder. Of course in the snake it is arranged a little differently, but these vital organs and parts perform the same for them as they do for humans.

Just like other animals, the snake has a body adapted for the life it leads. Unlike human beings, snakes keep growing until they die. The rate of growth is much faster when they are young and slows down as they grow older. An old snake may grow only a little bit, but it will still grow.

Every snake is strong for its size. Pound for pound, snakes have more muscles than many other kinds of animals. Humans have only 32 or 33 vertebrae in their backbones. Some of the larger snakes can have as many as 500 vertebrae. In general, the more bones a snake has in its backbone, the more agile it is. The symmetry of a snake skeleton is one of nature's most beautiful designs.

Because the body of a snake is usually long and thin, the organs must also be long and thin. The available space is limited, and as a result, some organs are reduced in size or missing. Most snakes, for example, have one large lung and one tiny lung, and in some cases they have only one lung.

Getting around without legs is not difficult for the snake. All snakes have at least three ways to move their bodies. Lateral, or serpentine motion is the most common way. To move forward a snake pushes sideways against rocks, sticks, and other objects found on the ground. By doing this the snake is able to literally "get a grip" on the ground.

Using the muscles attached to each of its ribs, the snake then pushes each set of ribs against a gripping point, starting with the ribs nearest to its head and working back towards its tail. As each set of ribs "pushes" in turn, the snake moves forward.

Caterpillar motion is another common method. "Concertina" motion is used when snakes must move in tight places, which means first the snake bunches itself together, than using its tail as an anchor, the snake pushes the front of its body forward. Sidewinding makes it possible for certain snakes to cross loose sand without sinking. To start this movement, the snake first arches its back and throws the front part of its body forward. This is the common movement you see in sidewinders in the desert.

We will continue talking about this in our next column, but right now I want to give you a few tips on how to avoid a snake bite when out in our beautiful parks and mountains.

Always read about the poisonous snakes that are native to Maryland, or anywhere else in the country that you decided to visit.

Dress appropriately. Wear high-top boots and loose fitting pants. Let the cuffs hang outside the boots.

Do not make any sudden moves if you see a venomous snake or hear rattling. Snakes do not see very well, if you don't make any sudden moves. Be very careful when backing away, too, so you don't run into another one nearby.

Do not sleep on the ground. You may roll over on a snake while asleep or a snake may crawl in next to you to get warm. Always sleep in a tent not just out in the open on the bare ground.

Do not reach or step into places that you can't see clearly because a snake may be hiding. Never reach over your head while climbing, unless you can see where your hand is going, and look over logs before you step over them.

As alway, remember to try and get out an enjoy nature. It has so much to offer.

I dedicate this column to my foot doctor who is one of the best, and to my mother who has been ill. May you make a full recovery.

I also wanted to give a "thank you" to my snake clients and all of you who email me with your questions. I love helping whenever I can.

Tammy McCormack is a Maryland-licensed DNR professional snake trapper. She writes an online column for You may reach her at

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