8 fascinating things you probably didn't know about the rat snake

Most people, when they see a snake slither through the grass, don't want anything to do with it. That’s to be expected, but if that snake is a rat snake, and in much of the US, the odds are decent, backing away slowly is about all you need to do. These are surprisingly intelligent animals, ecologically vital but without venom, quietly holding together whole suburban and rural ecosystems. Here’s why they deserve a second look.

They're basically America's original pest control
Rat snakes are constrictors that specialize in rodents. They hunt mice, rats, chipmunks, and voles with an efficiency no trap or rodenticide can match. Rat snakes do a clean job, at no cost to the homeowner or the environment. Chemical rodent control, on the other hand, carries real risks, including secondary poisoning in hawks, owls, foxes, and even household pets.

They are so effective because they can get into tight spaces, such as wall voids, attics, and underground burrows. They follow scent trails back to the rodent nests and wait them out. One adult rat snake can eat 10 to 15 adult rodents in one month, and it keeps doing so year after year in the same territory.


They are smarter than their reputation would suggest
Snakes, in general, are dismissed as instinct-driven automatons. Science says otherwise. According to a study published in the Journal of Applied Animal Welfare Science, rat snakes in more complex, stimulating environments solved problems faster, adapted faster to new situations, and exhibited distinctly more flexible behavior than snakes housed in bare, standard conditions. Not only were the enriched snakes less stressed, but they were demonstrably more competent. The study used a split-clutch design with black and yellow rat snakes, so its findings are particularly clean from a control perspective.

In summary, rat snakes have the ability to learn, adapt, and interact with their environment in ways that challenge the notion of reptiles as reactive animals.

They go a lot further than you would expect
Rat snakes are not ambush hunters, waiting for dinner to walk by. They are active foragers with defined home ranges. They move between habitats, ground, trees, and water, with a flexibility that is unusual even among snakes. They are good enough climbers to raid bird nests high in tree canopies, and many species are able swimmers, hunting frogs and fish in freshwater streams.

In their study in the Canadian Journal of Zoology, Weatherhead and Hoysak studied the radiotelemetry of black rat snakes and found that the snakes have stable home ranges for all seasons, return to the same hibernation sites year after year, and, in the case of males, actively patrol territories more than three times the size of females during mating season. They are not animals wandering aimlessly across the landscape. They know where they are, where they’re going, and why.

Their defense is theatrical, not dangerous
When a rat snake feels cornered, it doesn’t immediately bite. It puts on a show. Many species will rapidly vibrate their tails against dry leaves or brush, convincingly mimicking the warning rattle of a rattlesnake, making most predators (and people) back off immediately. If that doesn't work, they release a pungent musk, which is perfectly safe but very unpleasant, to make themselves less appetizing.

These animals really only bite as a last resort. They would rather bluff their way out of a confrontation than waste energy fighting a battle that they might lose.

The rat snakes you're most likely to encounter in the US
There are several species of rat snake in North America that are worth knowing on sight.

One of the largest snakes on the continent, the black rat snake (Pantherophis obsoleta) often exceeds six feet in length, with a shiny black back and white belly, hard to mistake once you know what you’re looking at.

Smaller and arguably the most visually striking of the bunch, the Southeast native corn snake (Pantherophis guttatus) sports rusty brown and orange-red blotches outlined in black against a pale chequered belly. It’s also the most popular pet snake in the US for a reason, being docile and manageable.

The eastern rat snake (Pantherophis alleghaniensis) runs along the Southeast coast from the Carolinas down to Florida, changing from grey and blotchy in juveniles to yellow, orange, or tan in adults.

The grey rat snake (Pantherophis spiloides) is found between the Mississippi River and the Appalachians. You can tell it by its rough, heavily keeled scales and its gray-on-gray blotched pattern.

Many of these species are nicknamed ‘chicken snake,’ and they deserve the name, because they’ve been raiding henhouses and stealing eggs since people started keeping chickens.

What to do if you find one
If you find a rat snake in your yard, coiled near the foundation or exploring the garage, the best move is the simplest one: leave it alone. It is not there to stir up trouble. It is there because something brought it there, most likely a mouse or a chipmunk, and it will move on when it is done. You don't have to move it, and most wildlife biologists don't think it particularly helps the snake.

Several species are widespread in the eastern US, especially the black rat snake, the corn snake (actually a rat snake), and the grey rat snake. None of them is a major threat to humans, and all are quietly working for free to keep local rodent populations in check.