Snakes play role as natural rodent, vermin control

Let’s talk about a group of reptiles that perform great services to us and the environment in terms of rodent and vermin control.  Probably more than any others, these reptiles evoke emotions ranging from reverence to fear and have been worshipped, used as symbols of healing and regeneration, and/or wantonly slaughtered, excessively hunted, and seen as dangerous or evil by human cultures throughout time. This group is the often misunderstood and underappreciated Squamates; more commonly referred to as snakes!

Snakes are sometimes described as "lizards without legs."  However, to describe a snake this way is similar to saying that a bicycle is the same thing as a car! Although lizards and snakes are related to each other (just as bicycles and cars are both wheeled vehicles for traveling from place-to-place) there are many differences between them! Snakes certainly lack the legs of lizards, but serpents are very specialized and well-adapted to varying modes of life. Perhaps briefly describing a few of their adaptations will help you gain, if not a great liking of snakes, at least an appreciation and admiration for our many resident snakes.

Among many adaptations, snakes have large numbers of extra ribs and vertebra and excellent musculature, giving their tube-like body great agility, flexibility, and speed. Belly scales (referred to as ventral scutes) are usually enlarged and, along with the ribs, help in crawling, climbing, digging, and swimming: all accomplished without legs!

Also, snakes usually have only one functional lung, no urinary bladder, no sternum connecting their ribs, a extendable glottis allowing them to breathe while swallowing prey items, and very flexible and mobile bones in their lower jaws and skull. Snake skulls are called kinesthetic; referring to the skull’s ability to stretch and move to accommodate swallowing whole prey items without chewing! Almost all of our area’s venomous snakes are in a group called Pit Vipers and have large, hinged, hollow (hypodermic) fangs connected to enlarged poison glands. Their venom is used to help capture and subdue prey and, as a last-resort, self-defense. Snakes usually have more than one row of upper teeth which are curved backward to help secure and swallow prey.

Additionally, a snake’s sense of smell is associated with its tongue and a specialized organ in the roof of its mouth called Jacobson’s Organ. This special organ contains sensors for sampling the air or soil on the snake’s tongue tips. Finally, pit vipers have special, heat-sensing pits between their eyes and nostrils which allow them to locate warm, living prey in complete darkness.

Let’s look at a few of our area’s larger resident snakes that help with rodent and pest control around farms and towns! The three species we will describe are all non-venomous and, although large in size and primarily active during the daylight hours, are usually fairly inconspicuous in our neighborhoods. They are the Great Plains Rat snake, Western Rat snake, and the Bullsnake. All are known as Colubrids; which in Latin translates literally to snake! These snakes, most often strike at and catch prey in their mouths then rapidly coil their bodies around and constrict, or squeeze, their prey in order to subdue it before swallowing their meals. Their numerous, backward-facing teeth and muscular bodies prevent the prey animal from escaping. The eyes of these snakes have round pupils (a characteristic of most, but not all, non-venomous snakes) and both Rat snake species have a ventral, divided cloacal/anal plate scale at the base of their tails. The larger-sized Bull snake has an undivided anal plate scale at the bottom base of its tail.

Both Great Plains and Western Rat snakes are widely distributed in our area. These snakes are very adaptable and occur in a variety of habitats. Great Plains Rat snakes can be found throughout our area associated with rocky areas, streams and rivers, woodlands and pasturelands, grasslands, dry gullies, and abandoned dwellings and structures with resident, rodent populations. Western Rat snakes are strong climbers and are more often found in woodlands and areas with large trees (including our cities and towns). Western Rat snakes are found along river and stream floodplains as-well-as other habitats also frequented by the Great Plains Rat snake. The Western Rat snake is a common backyard snake in urban areas, parklands, and suburbs with large trees. Colors and patterns vary between the two, but the Great Plains Rat snake usually has a set of dark-colored scales that form a distinctive spear shape on the top of its head (with the point facing between its eyes); whereas the head of the Western Rat snake is usually a more uniform, dark gray in color. Both species usually have single row of large, dark, brownish blotches extending down the center of their backs with the Great Plains Rat snake having two or more rows of smaller, dark spots on its sides; whereas, the Western Rat snake has a single row of dark, side spots.  A distinctive feature of the Western Rat snake is the reddish-colored skin found between its body scales. Prey of both species primarily consists of small rodents such as mice and rats, but they will also catch and consume small birds and bird eggs, and occasionally, frogs and lizards!

Bull snakes are larger, heavier-bodied, and more ground-dwelling than Rat snakes. Although body colors vary, Bull snakes are often distinguished by a robust, heavy body with a row of large, dark, brown, square blotches down the middle of the back with a mosaic pattern of smaller, dark blotches down the sides. The dark blotches are more distinct against its tan-to-yellowish base color closer to the head and tail areas and tail blotches form ring-like bands. A dark-colored line is found between the eyes and extends down the sides of the head to the end of the snake’s mouth. The belly is usually yellow colored.

Although large in size, the Bull snake is essentially harmless to humans as it forages through our area’s prairies, plains, rocky areas, barns, and other structures in search of rodents and other prey items. Bull snakes are said to have a decided preference for cultivated fields and other locations where they can find a large, ready, food supply of rodents! Other prey items include small rabbits, ground squirrels, prairie dogs, and ground-nesting birds. Contrary to a popular belief, Bull snakes do not commonly kill rattlesnakes; however, they may reduce rodent populations at a location; thus, causing other species of snakes to leave in search of better hunting. An unfortunate defense tactic of Bull snakes is to coil into the characteristic ‘S-shaped’ pose of rattlesnakes, hiss loudly, and raise and vibrate their tails when threatened and, as a result, many Bull snakes are misidentified and mistakenly killed by humans. Calm examination of the smaller head, tail with no rattles, and differences in color and body patterns will help you distinguish between Bull snakes and rattlesnakes.

The next time you encounter these three common area snakes, please remember some of their remarkable specializations and, above all, the beneficial services that they perform for us by significantly reducing populations of pests and vermin, such as mice and rats, by natural means! Then, even if you can’t grow to love snakes, at least you’ll have a greater understanding and appreciation of them.

This article originally appeared on Wichita Falls Times Record News: Snakes play role as natural rodent, vermin control