Snakes aren’t at the top of most people’s “favorite animal” list. But they have a purpose and can be useful in rodent control on farms.
Anna Wiker, outreach coordinator with the Kentucky Master Naturalist Volunteer Program, is aware that many people aren’t fond of snakes. “Snakes can be an environmentally friendly aid to on-farm pest control,” she said. “You don’t have to like snakes, you just have to be coworkers – pass by each other in the barn and pretend you don’t see each other.”
Each farm is its own ecosystem, and Wiker said humans are apex predators within those ecosystems. “We bring in animals like the Norway rat,” she said. “It’s an introduced species in many areas, and one that’s detrimental to poultry.”
A common first response after sighting a snake, owl, hawk or coyote is to remove the predator from the ecosystem. “When you start removing pieces of the ecosystem, there’s an abundance of lower-level organisms that often cause problems for farmers,” said Wiker. “Insects, rats, mice, rodents, ticks and parasites of all kinds experience a population boom when predators are removed.”
Wiker said there’s a lot of drama in the reptile community about distinguishing black snake species, which is why rat snakes are known by several names. At one time, all similar black snakes were lumped together and referred to as “black rat snakes.” Today, rat snakes are classified in the genus Pantherophis and split into different species.
This snake group includes Eastern rat snakes, gray rat snakes, Western rat snakes, Eastern fox snakes, Great Plains rat snakes, and corn snakes. They vary in coloration and region, but all are considered rat snakes and function similarly in the environment.
Markings on rat snakes are dark or patterned, and sometimes more defined in younger snakes. Rat snakes can grow up to six feet long.
“Rat snakes occur in the U.S. east of the Great Plains,” said Wiker. “That isn’t a one-size-fits-all, but in general, they are an East Coast species.”
All rat snakes have similar biology and behavior, and it’s the latter that earns them the reputation of being troublesome around poultry. While rat snakes prefer rodents, they also eat eggs and nestlings.
Rat snakes are generally comfortable around humans and live in buildings, barns and suburban areas. Shed skins are often found in basements, attics or outdoors in wood piles, indicating a healthy population.
People often distinguish venomous from non-venomous snakes in two ways: eye shape (round vs. vertical pupils) and head shape (wedge-shaped vs. rounded) – neither of which is reliable. However, rat snakes can flatten their heads into wedge shapes to mimic venomous snakes.
“Rat snakes are constrictors,” said Wiker. “They stalk their prey, loop the coils of their body around it, then tighten and cause cardiac arrest. They are also arboreal in their hunting habits, which means they climb around anywhere. Nothing anywhere is safe from a rat snake. If you see a snake and wonder how it got somewhere, it’s probably a rat snake – they are excellent climbers.”
The rat snake, often referred to as a black snake, is characterized by shiny black scales, slender body and ability to move quickly when necessary. Photo by Sally Colby
Rat snakes sometimes exhibit defensive behavior much like that of a rattlesnake. “A rat snake puts its tail in dry leaves and vibrates it quickly to produce a sound similar to a rattlesnake tail,” said Wiker. Rat snakes are one of many species do this.
Some venomous snakes, such as the Eastern copperhead, share their range with rat snakes. The copperhead’s markings are a uniform pattern of triangular bands that look like Hershey’s Kisses. Their scales are rough compared to the smooth scales of a rat snake. They also have an “angry” scale above the eye that gives them a frowning appearance.
The Eastern timber rattlesnake may look like a rat snake, but they’re hefty and thick compared to the long, agile rat snake. “Rattlesnakes and copperheads and other venomous viper species are big, chunky, slow-moving snakes,” said Wiker. “When in doubt, always be careful. If you’ve been bitten by a snake and you don’t know for sure what it was, seek medical attention.”
Farmers willing to tolerate rat snakes will be rewarded with the reptiles’ penchant for eating up to nine pounds of rodents each year. Although it’s close to impossible to keep rodents and snakes out of a barn, rat snakes remove reservoir species for tick-borne illnesses. Nothing survives the snake’s digestive system, so ticks (on rodents) are removed from the environment.
Snakes can also remove rodents that may spread disease to poultry. A 2024 study found that rats act as mechanical carriers via their fur or saliva for avian influenza (H5N1). Rats are continually exposed to wild bird droppings as they travel throughout the farm, so a healthy rat snake population can help curb disease spread.
To keep rats out of livestock housing, eliminate feed spillage and secure all food sources. Make it difficult for rats to exist in the environment. Snap traps are a reasonable control option for a minor rat problem. Dogs and cats can also be reliable controls.
The other component is accepting that snakes act as a repellant. “There are studies that suggest having snakes around the barn and property will repel rodents,” said Wiker. “Even if the snakes don’t catch rodents, rodents pick up on the smell and the shed skins left behind.”
Rodenticides are usually nerve poisons or anticoagulants. These chemicals are non-selective and will kill dogs, cats and wildlife. However, a mixture of corn gluten and salt causes rat death by dehydration. With this method, other animals can consume dead rats without the risk of secondary poisoning.
It’s possible to have a friendly co-working relationship with snakes. “Snakes are not rat poison and won’t eliminate all the rats, but they are a component of an ecologically friendly pest management plan,” said Wiker. “Snakes might be eating eggs but think of what level of loss is acceptable. No matter what the situation, you might face some loss from predation.”
by Sally Colby
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