Nightmare Rattlesnake Den or a Surprisingly Social Slumber Party?

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A single rattlesnake can be rather unnerving, but just imagine stumbling upon a den teeming with dozens — or even hundreds — of rattlesnakes! This is exactly what you’ll see in this video. While it may sound like something straight out of a nightmare, this unusual phenomenon is very real and more common than you might think!

Why Do Rattlesnakes Gather in Dens?

Like all reptiles, rattlesnakes are cold-blooded animals, which means they rely on external sources to regulate their body temperature. You might catch a glimpse of one basking in the sun on warm days or retreating to a shady spot during the high heat of summer. But what do they do in the winter? Well, that’s when rattlesnakes enter a hibernation-like state called “brumation“.

During brumation, rattlesnakes seek out a safe place to wait out the winter’s cold. Often referred to as “hibernacula”, these dens could be anything from crevices in rocks to underground burrows or piles of debris. Prairie rattlesnakes (Crotalus viridis) like those in this video, often brumate in natural cavities or underground areas, holes made by other animals, or cracks in rocky outcroppings.

However, even with this protection, staying warm in freezing conditions can be quite a challenge. That’s why many snake species, including prairie rattlesnakes, hibernate together in large groups. By congregating in these shared spaces, the snakes can share body heat and conserve energy. Other animals may also share these dens, including amphibians, reptiles, and even small mammals.

Rattlesnake “Rookeries”

Rattlesnake dens don’t just serve as warm winter shelters, they also make great nurseries. Pregnant rattlesnakes sometimes gather in specialized dens called “rookeries” — or rattlesnake nurseries — to give birth and care for their babies. Although rattlesnakes aren’t particularly social animals, they demonstrate surprising cooperation when it comes to protecting their young.

Unlike most other reptiles, rattlesnakes give birth to live young rather than laying eggs. Since not all females give birth at the same time, these rookeries allow the mothers to share responsibilities and guard the den’s new additions. For the first few weeks of life — usually until they shed their skin for the first time — mother rattlesnakes dedicate themselves to protecting and watching over their babies, ensuring the young snakes are safe from predators and don’t wander off too far.

Misunderstanding Rattlesnake Behavior

Despite how movies and television commonly portray them, rattlesnakes aren’t aggressive animals. When faced with threats, rattlesnakes typically retreat or hide — they actually rarely attack. In fact, researcher Cale Morris conducted an experiment with 175 rattlesnakes and only six of the snakes tried to strike when threatened!

Where Are Rattlesnakes Found?

Rattlesnakes are quite common in the southwestern United States, but they can be found in nearly every U.S. state. They also live in parts of Canada, in addition to regions of Mexico, Central America, and South America.

The rattlesnakes seen in the video above are prairie rattlesnakes in Montana. Prairie rattlesnakes can be found from southwestern Canada down through the western U.S. and into northern Mexico.