Photograph by Tom Uhlman, Alamy
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Black rat snakes are non-venomous species commonly seen in the eastern United States.

Photograph by Tom Uhlman, Alamy

Snakes Infest House in Maryland—How Did It Happen?

The invasion of the black rat snakes, which may have been seeking out a winter refuge, is a "freak occurrence," one expert says.


Everything seemed normal when the Brooks family moved into their dream home near Annapolis, Maryland, last December.

That is, until spring came—and the snakes arrived.

Snakeskins and droppings became commonplace in the house. As did actual black rat snakes (Pantherophis obsoletus), which ranged from small hatchlings to full-grown seven-footers. By April, the family had evacuated the premises and filed a $2 million lawsuit against their real estate agent, according to a local newspaper, the Capital Gazette.

The good news for other homeowners is such snake infestations are "really unusual. It's not something most people should expect or fear," says David Steen, a wildlife ecologist at Auburn University in Alabama.

For some reason, the non-venomous reptiles had "settled on this house as a congregation point, maybe for denning in the winter," Steen said.

Snakes are ectothermic, which means their body temperature fluctuates with their environment. When it gets cold, the serpents find a cozy place to curl up and wait out the winter.

That could be anything from a tree stump to a rocky crevice to—you guessed it—a warm house.

Freak Occurrence

Even if such instances are rare, the house in Maryland isn't the first report of a domicile that would make Indiana Jones squirm.

In one house in Idaho, "garter snakes were crawling through cracks in the house's foundation and using it as a hibernaculum [a place to spend the winter]," says Michael Dorcas, a snake expert at Davidson College in North Carolina.

It's likely the snakes had always used the area as a hibernaculum, and the house was simply built on top of the animals' territory. (Related: "Year of the Snake: The Serpent Behind the Horoscope.")

Scientists have also found wild places where snakes congregate, including the Narcisse Snake Dens of Manitoba, Canada (map), where 75,000 garter snakes mate in great, writhing masses. It's the world's largest known gathering of snakes.

If You're Scared of Snakes, Don't Watch This June 25, 2014 - Every year, thousands of snakes gather at the Narcisse Snake Dens in Manitoba, Canada. It's billed as the largest gathering of snakes anywhere in the world. Manitoba’s climate and geology make it the perfect place for red-sided garter snakes to live and mate. It has become a tourist attraction, but it’s not for the faint of heart. 

For a news article about the Narcisse snake gathering, click here.

But rat snakes, says Steen, aren't really known for doing this. So the case of the Maryland house, he says, is likely a "freak occurrence."

How Do You Prevent A Snake Infestation?

While rat snakes are generally shy around people, their prey can draw them close to people. In fact, because their diet primarily consists of pest animals like rats and mice, they are usually looked upon as a handy animal to have around.

"They like farms, barns, and even neighborhoods," says Dorcas, who has studied the species. "And they climb really well."

Though the rat snake is clearly capable of Mission Impossible-style maneuvers, a tightly sealed home should be all it takes to prevent the animals from becoming unwanted houseguests.

Watch a video of a rat snake trying to steal eggs.

Cracks in doorframes and windowpanes, holes in walls, and crevices in a home's foundation can all provide access to these nimble creatures.

Know Your Reptiles

Black rat snakes, one of the most commonly encountered species across the eastern U.S., are often confused with venomous snakes, Steen adds.

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Red-sided garter snakes, which can form "mating balls" in the tens of thousands, are also harmless to humans.

This can lead people to harass or kill reptiles that pose little to no threat. In fact, Steen scours social media each day for these false IDs and engage with the public about the actual species in their backyards. (Hint: It's usually #NotACottonmouth.)

But even snake experts say they'd prefer not to live in a house full of rat snakes. (Read about the world's most venomous snakes.)

"If you go to the bathroom at night and you step on a snake in the hallway, it's going to startle you," says Dorcas.

"Even if you like snakes, you don't want that."

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