Thursday, June 20, 2013

Snakes alive!

There are many myths and misunderstandings surrounding snakes, and this misinformation not only gives these reptiles a bad rap, but needlessly jeopardizes their lives. There are 2400 snake species worldwide with 52 species residing in Missouri, 5 of which are venomous.

Snakes are members of the Class Reptilia, a group that includes turtles, alligators, crocodiles, and lizards. The reptiles are cold-blooded animals, which means they rely on the heat of the environment to warm their blood. Snakes move faster in warmer temperatures and slower when it is cooler. Snakes and other reptiles will often lay on a flat surface, such as a rock, to bask in the sun to increase their metabolism.

A snake's backbone consists of 200 - 400 vertebrae and special muscles that allow for flexibility and the ability to move. There are a number of different ways snakes can move. Some move forward by a side-to-side movement, or in a straight line by literally walking on their ribs. Most snakes use plants, rocks, sticks and other natural irregularities as shove off points. All snakes can swim.

Snake bodies are covered with scales. Without this protective armor, snakes could not move over rough or hot surfaces like tree bark, rocks and hot desert sand. Their scales are nearly waterproof and help keep water out when wet. Rough belly scales allow the snake to keep their grip on branches and push off surfaces when they move.
 Snakes can hear low frequency sounds and feel vibrations. That's why snakes often sense your presence long before they see you. They have heat sensors in pits on the sides of their faces or on their lips. These heat sensors allow snakes to successfully hunt their prey in complete darkness.

Snakes must swallow their food whole, and their jaws are adapted for this method of eating. Snakes can move their upper jaw away from their lower jaw and the left side of their lower jaw from the right side. This expandability, due to extremely elastic muscles and ligaments in the throat and between bones in the jaw, allows snakes to swallow animals up to 3 times the diameter of their head. The snake's teeth also help it to swallow. The teeth are sharp and curve toward the rear of the mouth. While swallowing their prey, the curved teeth help in walking the snakes meal down their throat. Because they can eat such huge meals at one time and are cold blooded, snakes don't eat as often as other animals. During times when food is scarce, most snakes can get away with eating just a few times a year.

Some snakes eat insects and insect larvae, fish, frogs, tadpoles or crayfish, rodents, small birds and their eggs. Their food choices play an important role in the food chain. They help to keep the populations of unwanted animals, such as rats and mice, under control.

Shedding is an important process in the life of a snake. Young snakes will shed every four or five weeks during the summer, whereas adults may shed once every six or eight weeks during that same time period. Rattlesnakes shed 2 - 5 times in a year and a new segment is added at the base of the rattle at each shedding. Determining the age of a rattlesnake by the number of segments in their rattle is not possible because old segments weaken and may break off of the rattle.

About half of Missouri's snakes lay eggs; the rest give birth to fully developed young.

Females will select rotten logs or stumps, leaf litter or sawdust piles in which to deposit their eggs. These eggs are elongated and have a tough, leather shell. Some egg-laying snake species are black rat snakes, bullsnakes, kingsnakes, rough green snakes.

The snakes that give birth to fully developed young are water snakes, garter snakes, brown snakes copperheads, cottonmouths and rattlesnakes.

A few years ago, I came across an Eastern Hognose Snake (Heterodon platyrhinos). As the name implies, the snout looks something like a hog nose.
This species of snake live around sandy areas or open woods with loose soil.  The Hognose Snake has an interesting way of defending itself against perceived danger. When threatened, this harmless snake will spread its neck like a cobra and hiss. It is not uncommon for this snake to roll over and play dead. These snakes mostly feed on toads but are also known to eat frogs or salamanders.

Every summer without fail, I come across Black Rat Snakes (Elaphe obsoleta obsoleta).
These snakes live in a wide variety of habitats: rocky, wooded hillsides, near rivers, in or around farm buildings. Black rat snakes are known for  their remarkable ability to climb up trees. Their diet mainly consists of rodents, birds and bird eggs.

I've recently learned that newly hatched black rat snakes look completely different from their adult counterparts.
These young snakes are tan to gray with distinct black or dark brown blotches along the back and sides of the body. There is a black band on the head that crosses from eye to eye and extends down at an angle toward the mouth. The colors gradually change as the young snake matures. The characteristic black color doesn't appear until the snake is 2 years of age.

All of Missouri's venomous snakes are pit vipers, which means they have an opening on each side of the head, called a sensory pit. A pair of hollow fangs are located on the front of the upper jaw. In daylight these snakes have eyes with vertical pupils (like a cat). Harmless snakes have round pupils.
 
Missouri Department of Conservation.
If you are squeamish about snakes, there are ways to avoid encounters, or at the very least, alert the snake to your presence so that it can begin to make its escape before you notice it.

1) If you can help it, avoid wet habitats such as swamps, wetlands and marshes.
2) It's a good idea to wear thick rubber boots or hiking boots that cover the ankles when walking on trails. These will protect your feet, ankles and lower legs.
3) Snakes are especially fond of rocks and logs. When walking, never place your hands or feet under large rocks and logs. On that same note, it is also a good idea to step on those rocks and logs before walking over them.
4) Piles of discarded wood, scrap corrugated steel roofing, burlap, slabs of bark, and rock piles provide hiding places for snakes and their prey. Remove these objects if they are around your yard.

And ease your mind with these facts on snakebites. A snake rarely will go out of its way to attack you. In fact, most bites occur when a person is trying to handle or kill a snake. Every year in the US, 8000 people are bitten by venomous snakes, but only a dozen die from these bites. By comparison, 120 people die each year from bee stings and 150 people die from lightning strikes.

It is possible to appreciate these incredible animals from a distance. Snakes will rarely, if ever, approach you. If you respect their space, the snake will respect yours.

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