This time of year I get many questions about snakes. The one thing I tell people is if they want to win a bet, ask someone how many species of poisonous snakes there are in Missouri. Do you know the answer?
Snakes belong to the class Reptilia, a group that also includes turtles, alligators, crocodiles and lizards. There are over 3,000 named species of snakes globally. Missouri has 51 species and subspecies of snakes.
The answer to the question is zero. Plants and some other things are poisonous, snakes are venomous, of which we have five species: Timber rattlesnake, Eastern Massasauga rattlesnake, Western Pygmy rattlesnake, Western cottonmouth and the Copperhead.
All venomous snakes have eyes with vertical and elliptical pupils like a cat, while all harmless snakes have round eyes. Venomous snakes also have a single row of scales on the underside of the tail while the harmless snakes have two rows of scales. The old adage of a triangular shaped head to identify venomous snakes is not reliable.
All snakes are ectothermic (cold-blooded) which makes them unable to regulate their body temperature. They must seek shelter during excessive heat and extreme cold.
Snakes have 200-400 vertebrae depending on the species which permits extreme flexibility. Some snakes climb trees and all snakes can swim. They can also strike from any position. The snake’s long forked tongue is used to pick up odors.
All snakes eat other animals and are classified as carnivorous. Snakes must swallow their food whole and some can engulf animals three times the diameter of the snake’s head. The lower jaw is loosely joined to the skull and the upper jaws are moveable. A snake grabs its prey by the head and engulfs it by advancing first one side of the jaw and then the other. The snake’s teeth are sharp and curve toward the rear of the mouth to hold the prey and prevent escape. Some snakes such as water snakes and garter snakes eat their prey alive while venomous snakes usually inject venom into the animal and swallow it after it’s dead. Several Missouri snakes such as rat snakes, king snakes, milk snakes and bullsnakes kill by constriction.
Food habits of Missouri snakes are as varied as the types of snakes we have. Some, such as the rough green snake, eat insects and insect larva. Others, like water snakes, eat fish, frogs, tadpoles and crayfish. The black rat snakes, king snakes and bull snakes eat rodents, small birds and their eggs. King snakes are immune to the venom of venomous snakes and will kill and consume them if given the opportunity.
In Missouri, snakes normally breed in the spring soon after they emerge from winter dormancy. About half of Missouri’s snakes lay eggs and the rest give birth to fully developed young. The size of the egg depends on the species and the number of eggs produced depends on the size of the female. The larger the female the more eggs she can produce. Snake eggs are elongated and have tough, leathery shells. As young develop within the egg, a small “egg tooth” grows at the tip of its snout which is used to slit the shell when hatching. Afterwards, the tooth is shed. Snakes, which retain their young until fully developed, are water snakes, garter snakes, brown snakes, copperheads, cottonmouths, and rattlesnakes. Snakes that develop within the female are normally born in mid to late summer.
All snakes shed their outer skin periodically as they grow. Young snakes usually shed every 4-5 weeks during warm weather, whereas adults may shed once every 6-8 weeks. In the case of rattlesnakes, a new segment is added at the base of the rattle at each shedding. In Missouri, rattlesnakes may shed from 2-5 times a year. As the rattle becomes longer, the old segments weaken and may break off so it is not possible to age a rattlesnake by counting the segments in the rattle.
About 8,000 people are bitten by venomous snakes each year in the United States. Fewer than five die. By comparison, about 120 people die annually from bee stings and 150 from lightning.
Snakes have a difficult time surviving, not only because of persecution but primarily because of habitat destruction (deforestation, pollution and urbanization). As with many animals whose numbers are declining, most problems associated with the plight of our native snakes result from a lack of understanding. People traditionally have been brought up to fear snakes so consequently snakes have not fared well in their relations with humanity. Psychologists have proven that Ophidiophobia, a fear of snakes, is acquired and not born within.
The smallest snake native to Missouri is the flat headed snake which averages 7-8 inches. The longest, the bullsnake, is from 50-72 inches.
As with all other wildlife, snakes are an important part of the natural food chain and play an important role in the balance of nature. Overall, snakes are a fascinating part of the natural world in which we live.
Few Missourians realize that all snakes native to our state are protected. The Wildlife Code of Missouri treats them as a non-game species and it is against the law to kill them. An exception to this rule is when a venomous snake, in close association to people, might result in someone being bitten.
Man’s heart, away from nature, becomes hard; (the Lakota) knew that lack of respect for growing, living things soon led to lack of respect for humans too. -Luther Standing Bear (c. 1868-1939)
