Introduction to the snakes of Oklahoma

2ndPeter | FlickrShown is a bullsnake (Pituophis catenifer sayi). One study of bullsnakes found that a single 2.5-pound bullsnake could consume 6.7 pounds of food in a six-month period. This approximately equals the weight of 12 pocket gophers. In another food study of bullsnakes, one individual was found to have eaten 35 mice at one meal. Considering the amount of damage that a single mouse can cause to crops, grain and food, a bullsnake is a very valuable ally.

Forty-six species of snakes are native to Oklahoma. Only six species (15%) are potentially harmful to humans. Venomous species include the copperhead, cottonmouth, western diamondback rattlesnake, timber rattlesnake, prairie rattlesnake and western pigmy rattlesnake. Snakes are found statewide and in all habitats. Some species thrive in urban and suburban environments. Given the large number of snake species, both venomous and non-venomous, it is important that Oklahomans learn to identify the species and learn more about this unique part of our state’s fauna.

Snakes, lizards, turtles and crocodiles form the group of animals known as reptiles. Reptiles are best known for having scales and/or bony plates and laying terrestrial eggs. Contrary to popular belief, snakes are not slimy, although the smooth, highly polished scales found on species such as the king snake may suggest this appearance. Other snakes have a ridge that runs down the length of each scale, giving the snake a duller, rougher look. Many reptiles are unable to maintain a constant body temperature and are often called “cold-blooded.” Biologists now prefer the term “ectothermic.” An ectotherm’s body temperature changes with that of its environment; snakes in the shade tend to have a lower body temperature than snakes found in open sunlight. Each species has a preferred body temperature that individuals attempt to maintain behaviorally.

On cool mornings, snakes often bask in the sun or warm themselves on rocks. At night, they may crawl onto highways, where they absorb heat before searching for food. To avoid overheating during the hottest months, many snakes become inactive during the day and come out at night. At low temperatures (below 60 degrees F) snakes become sluggish, and a continued drop in temperature (below 56 degrees F) initiates hibernation.

Habitat

Venomous snakes are found throughout the state. Cottonmouths, copperheads and pygmy rattlesnakes are usually found in moist environments. Prairie rattlesnakes are found in the prairies of western Oklahoma, while timber rattlesnakes inhabit the forested eastern half of the state. Western diamondback rattlesnakes are most common in southern and western Oklahoma, but their range extends as far north as Tulsa, Cherokee and Adair counties. Rocky outcrops providing shelter, basking and possible hibernation sites are a favorite habitat for copperheads and rattlesnakes. Where rocky outcrops are scarce, many different species of snakes often share dens for hibernating. 

The local dump is one habitat not often considered. Exposed trash and litter provide refuge for bull snakes and the small animals that snakes use as food. Snake populations can be controlled around homes by simply removing tall weeds, brush, trash, etc that provide potential cover. In an effort to attract snakes for study, biologists will often “seed” an area with large plywood or tin pieces, thus providing the cover essential to snake survival.

Snakes and man

We have more impact on the life of snakes than vice versa. Every day, we destroy precious habitat and pollute streams. Pesticides reduce the amount of food available to some species. Increasing pesticide levels are accumulating in the tissues and organs of snakes, possibly affecting their growth and reproduction.

The impact of snakes upon us is both positive and negative. Snakes are capable of consuming large numbers of rodent pests, many of which are carriers of disease and parasites that adversely affect livestock and human populations. One study of bullsnakes found that a single 2.5-pound bullsnake could consume 6.7 pounds of food in a six-month period. This approximately equals the weight of 12 pocket gophers. In another food study of bullsnakes, one individual was found to have eaten 35 mice at one meal. Considering the amount of damage that a single mouse can cause to crops, grain and food, a bullsnake is a very valuable ally.

Snakes are also making news on the medical front. Currently, much time and effort is being given to the research of venoms in association with a number of diseases. Unfortunately for snakes, we tend to accentuate the negative. Damage to livestock caused by snakes is minimal compared to other sources of injury. While a single snake can inflict a lot of damage to chickens, capture and removal of these individuals will often solve the problem.

For those individuals who fear or dislike snakes, there is an ongoing battle to kill snakes. This may temporarily reduce the number of snakes, but it can never eliminate them. As long as food and habitat are available, there will always be snakes. By altering habitat, a more permanent reduction in numbers of snakes can be achieved. Disposal of brush piles and scattered debris will remove cover for small mammals and snakes. Placing feed and grain in rodent-proof containers will reduce rodent numbers and thereby reduce snake numbers. Currently, there are no known snake repellents. Snakes can be kept out of houses by sealing cracks in foundations, and around windows, air conditioners and doors.

Following these few simple suggestions will help reduce the number of unwanted snakes around your home.