Western (Texas) Ratsnake

fullsizeoutput_1011Many years ago I was contacted to go to my son’s day care, which had some land and kept a few animals around a small barn. They said that a big snake had been eating the duck eggs, and the culprit had been spotted earlier in the day. I went over and had a look, and as I raked hay away from what appeared to be an old burrow in the floor of a stall, I caught sight of the dark coils of a ratsnake. After pulling about five feet of Texas ratsnake from her refuge, I then had to get a very unruly snake into the bag so that I could relocate her. A day or two later I took the snake to the wooded corridor of a large creek and tried to pose her for some photos before letting her go. This did not go particularly well; draping a big ratsnake along a log by the woods gives the snake an immediate plan for escape and a very impatient attitude about sticking around for pictures. Of course she turned and bit me. I stood, finger dripping blood into the creek, wondering how many hundred times I have been bitten by Texas ratsnakes. Meanwhile I did get a photo or two before the big snake climbed into the highest branches of a nearby pecan tree.

I wished her luck, and she would need it. Relocated snakes often do not do very well, because they learn to recognize a particular area (their “home range”) where they live, and when taken somewhere new, even if the habitat is pretty good, they may act as though they are lost, and wander without settling down. Many studies of translocated snakes show that they’re more likely to die, failing to avoid hazards and/or to take advantage of resources in the new location. However, sometimes a snake like this Texas ratsnake faces a dilemma: stay and be killed or get relocated and “lost.” At least in her new woodland, she had a chance.

While I stubbornly hang onto the name “Texas ratsnake,” this species was re-named a few years ago after improvements in the scientific understanding of the relationships among North American ratsnakes. Its proper name is now the western ratsnake, Pantherophis obsoletus. What used to be called the “black ratsnake” and “yellow ratsnake,” east of the Allegheny Mountains, is now the “eastern ratsnake,” Pantherophis alleghaniensis. In the middle part of eastern North America, they are Pantherophis spiloides, a new name for the gray ratsnake. West of the Mississippi River, they become western ratsnakes, but some habits are hard to break, and so I still call them Texas ratsnakes.

This species may be the subject of more run-ins with people than any other snake in our area. Lots of “snake calls” are generated by people seeing a Texas ratsnake in their trees or yards. Soon after eggs hatch at the end of summer, babies sometimes turn up in people’s garages and sheds. Lots of them are killed on the road each year. Yet somehow, they continue to be abundant year after year around parks and suburbs (as well as in more remote locations).

This is one of our longest snakes, averaging about 3.5 to 6 feet long, with a record length of seven feet, according to Werler & Dixon’s Texas Snakes: Identification, Distribution, and Natural History. Like several other ratsnake species, the Texas ratsnake’s body, seen in cross-section, is rounded on top and squared at the bottom, like a section of a loaf of bread. This is thought to aid them in climbing trees.

The adult snake’s fairly broad, flat head is dark gray on top, shading to white on the lips and chin. Starting with the neck, there is a pattern of dark saddles going down the back. The dorsal ground color may be yellowish-gray to gray or charcoal. Along the sides is another row of blotches, these being somewhat diamond-shaped. The skin between the scales of the neck and forebody generally includes reddish or orange color, more visible when the skin is stretched. Some of the skin between the scales within the blotches is light gray to white, showing as small flecks of white in a patch on the lower parts of the blotch. Add to this one further complexity of pattern – many adults have the suggestion of vague, smudgy stripes where the edges of the blotches seem to smear a little and join each other down the back. On the belly, the scales are light on the throat, darkening from front to back with large pale squarish blotches and then a mottling of gray and yellow toward the tail.

Texas rat snake - subadult female

A young adult Texas ratsnake with more yellow in the background color

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An individual with lots of gray color, though considerable red can be seen between the scales

Hatchling Texas ratsnakes have brighter and bolder patterns than the adults, with a light ground color so that the blotches stand out more. On the top of the head, juveniles have some dark spots and flecks, and a broad, dark band across the snout just in front of the eyes. That band then goes through the eyes diagonally to the jawline. The pattern darkens with age.

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Juvenile Texas ratsnake

Texas ratsnakes take advantage of a wide variety of habitats within roughly the eastern two-thirds of Texas where they are found. They occur in east Texas and down the Gulf Coast to Corpus Christi, and in central Texas to a little west of Wichita Falls, out to San Angelo, and southwest nearly to Del Rio. This means that they live in east Texas piney woods, bottomland hardwoods, cross timbers woodland, and savannas from north Texas down through the Hill Country. They are excellent climbers, and this may be one factor in their success, keeping them away from ground-based predators and people at least some of the time. While up in the trees, they may eat birds and their eggs.

My field notes and my memory indicate that I’ve found lots of Texas ratsnakes in patches of prairie, old fields with at least a creek nearby, and woodlands and forests. During the day, I have been more likely to find them by flipping cover such as discarded plywood or logs. I’ve seen a great many on back roads at twilight or at night, quite often in brushy or wooded areas, or within a short distance of a creek. Undoubtedly they use wooded creek and river corridors to move around in more dry, open areas further west in their range.

Both the accepted common name, “rat” snake, and the often used name “chicken” snake refer to some of their preferred food. A stomach contents study cited in Werler & Dixon, looking at 100 wild specimens in north Louisiana, found mice, rats, and a few squirrels and rabbits in their stomachs. This snake is more than happy to eat birds and their eggs. Coming upon nests, it may eat eggs or fledglings. A big adult reportedly can swallow an adult chicken. While this may not make the Texas ratsnake popular with either farmers or birders, it is simply doing its “job” and may eat enough rats that it does the farmer more good than harm.

The most memorable activity seen in Texas ratsnakes may be their belligerent self-defense when cornered or handled. When first approached, the snake may “make a break for it” or may stay where it is. I have often seen one pull its body into a series of short kinks and sit still, hoping that it won’t be seen. Once picked up, the snake thrashes in an attempt to get away, and may bite repeatedly while discharging musk from the other end. While some snake musk is only moderately disagreeable, musk from a Texas ratsnake is very offensive, a little reminiscent of burnt tires. But the open-mouthed gape while looking for an opportunity to bite is worse. Very commonly, having picked up one of these snakes, it remains coiled on one of your arms as if it were a tree limb while gaping at your hand or other arm as the obvious visible target. If your hand moves closer, the snake will strike, leaving a series of pinprick holes. Occasionally it will hold on and chew. It is important to remember that this only happens to humans who harass and pick up a ratsnake; an observer who simply watches and photographs will not be attacked.

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The famous Texas ratsnake gape, ready to bite the attacker

One additional note in defense of the Texas ratsnake, showing that biting is only self-protective and never because it wants to pick a fight: I have many times been able to pick up a Texas ratsnake by slipping a hand under it and supporting it while giving it no target that looks like an enemy. A freshly-caught ratsnake may crawl from one arm to the other as long as nothing comes at it like an attacker. However, this is in no way foolproof, and fairly often it pauses and seems to recognize that this is no tree, abruptly biting my arm. And again I would stress that I have never, ever been bitten by a Texas rat snake that I was  not handling or attempting to handle. They have no venom and they have no interest in becoming aggressive as long as they are left alone.

Spring mating results in the laying of a clutch of five to twenty eggs in June or July. The eggs are laid in rotting logs, in a protected area under leaf litter, in abandoned mammal burrows, or under rocks. It is also known to use above-ground tree cavities for nesting, and the description in Werler & Dixon notes that the tree cavity was used by perhaps four different females for communal nesting. The eggs hatch in August and September, and the baby snakes have much the same temperament as their parents!

(This article is adapted from one I wrote for the January, 2003 issue of the Cross Timbers Herpetologist, newsletter of the DFW Herpetological Society.)

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