Western Rat Snake

## Description

Pantherophis obsoletus – also known as the western rat snake, black rat snake, pilot black snake, or simply black snake – is a non-venomous species of Colubridae found in central North America. No subspecies are currently recognized. Its color variations include the Texas ratsnake. Along with other snakes of the eastern United States, like the eastern indigo snake (Drymarchon couperi ) or the eastern racer (Coluber constrictor ), it is called 'black snake'.

## Appearance

The Western rat snake is a large non-venomous snake found in central North America. Juveniles are strongly patterned with brown blotches on a gray background. Darkening occurs rapidly as they grow. Adults are glossy black above with white lips, chin, and throat. Sometimes traces of the "obsolete" juvenile pattern are still discernible in the skin between the scales, especially when stretched after a heavy meal. Aside from the usual variety that is black or has patches of black on a lighter background, color variations include a brown-to-black variant, often with tinges of orange or red, that can be found in southern Oklahoma, Texas, and Louisiana.

## Distribution

Western rat snakes are found west of the Mississippi River, from eastern and southern Iowa southward through Missouri and Arkansas to western Louisiana, westward to eastern Texas, northward through Oklahoma, and eastern Kansas to southeastern Nebraska. Rat snakes live in a variety of habitats ranging from a rocky hillside to flat farmland. They prefer hardwood forest and woodland, wooded canyons, swamps, rocky outcroppings, wooded areas near streams and rivers, farmland near woods, around barns, old fields, and abandoned houses.

## Behavior

Western rat snakes are diurnal creatures. They are usually solitary but during winter they hibernate in dens, often with copperheads and Timber rattlesnakes. Western rat snakes are excellent climbers and are able to climb the trunk of large mature trees without the aid of branches; they are also good swimmers. These snakes are constrictors, meaning they squeeze their prey, coiling around small animals and tightening their grip until they can no longer circulate blood and die of profound hypotension, before eating them. When not fully grown, rat snakes are prey to many animals, including other snakes. When startled, they may freeze and wrinkle themselves into a series of kinks. If they feel further threatened, they may flee quickly or perform a tail vibrate (potentially a form of mimicry, which makes them sound like rattlesnakes). They are also capable of producing a foul-smelling musk, which they will release onto predators if picked up. They spread the musk with their tails in hopes of deterring the threat. When cornered or provoked, Western rat snakes are known to stand their ground and can become aggressive.

## Diet

Western rat snakes are carnivores that often consume mice, voles, rats, and other small vertebrates they can catch. They also eat other snakes, frogs, lizards, chipmunks, squirrels, juvenile rabbits, juvenile opossums, songbirds, and bird eggs.

## Reproduction

Western rat snakes breed in late May and early June. Males use pheromones to attract females passing through their territories and will initiate the mating process with the female. Five weeks after mating the female lays about 12-20 eggs in a hidden area, under hollow logs or leaves, or in abandoned burrows. The eggs hatch about 65-70 days later from late August to early October. The hatchlings are 28-41 cm (11-16 in) in total length and they look like miniature fox snakes. They are independent from birth and don't require parental care.

## Population

### Population threats

There are no major threats to Western rat snakes at present. However, locally they do suffer from the loss of habitat through deforestation and different forms of intensive development.

### Population number

According to IUCN, the Western rat snake is locally common and widespread throughout its range but no overall population estimate is available. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.