For most homeowners, the crawl space is an “out of sight, out of mind” area. It’s dark, it’s dirty, and it’s full of spiders. But for the snakes of Louisville, your crawl space is a five-star winter resort.

As reptiles, snakes are ectothermic (cold-blooded). They cannot generate their own body heat. If they are caught outside in freezing temperatures, their blood will literally freeze, and they will die. To survive a Kentucky winter, they must find a hibernaculum—a secure place below the frost line where temperatures remain stable and above freezing.

In the wild, they use deep rock crevices, caves, or stump holes. In the suburbs, they use your house.

Why Your Crawl Space?

Your crawl space offers three things that a hollow log cannot:

1. The Heat Island Effect Even if your floor is insulated, your crawl space absorbs heat from the house above. Ductwork often leaks warm air, and uninsulated hot water pipes radiate heat. This keeps the crawl space significantly warmer than the outside soil, ensuring the snakes never freeze.

2. Easy Access Most crawl spaces in Louisville are not sealed tight.

• Vents: Older homes often have vents with rusted or missing screens.
• Doors: The access door is often loose, rotted, or leaves a gap at the bottom.
• Pipes: Gaps around water and sewer lines entering the foundation are perfect highways for snakes.
• Cracks: Settling cracks in block foundations allow entry.

3. The Buffet Snakes follow food. If you have mice or crickets living in your crawl space (which is very common), the snakes will follow the scent trail right in. Once they are in, and they realize it’s warm, they decide to stay for the winter.

The “Slumber Party” (Communal Denning)

This is the part that gives people nightmares. Many snake species, particularly Black Rat Snakes and Garter Snakes, den communally.

They use pheromones to mark safe trails. If one snake finds a perfect winter den (your crawl space), it leaves a scent trail. Other snakes smell this and follow it. It is not uncommon to find multiple snakes—sometimes intertwined in a ball to conserve heat—sleeping together in a corner or on top of the vapor barrier.

Note: They are not “nesting” or breeding in winter. They are in a state called brumation (reptile hibernation). They are lethargic, they don’t eat, and they barely move.

The Danger of Spring

The problem often goes unnoticed until spring. As temperatures rise in March and April, the snakes wake up. They are hungry and active.

• They may try to find a way out and get lost, ending up in your living area.
• They may start hunting the mice in your walls.
• You might open the crawl space door to store something and be greeted by a very awake, very large snake.

Prevention: The Fall Seal-Up

You must seal your foundation before winter sets in (ideally September or October).

The Risk of Sealing Too Late: If you seal the vents in December or January, you might trap the snakes inside. They will be stuck there until spring, at which point they will become desperate to escape, potentially forcing their way up into your kitchen or bathroom.

What To Do:

1. Inspect Vents: Replace any torn screens with 1/4 inch hardware cloth.
2. Check the Door: Ensure the crawl space door fits tightly. Install weatherstripping if needed.
3. Seal Penetrations: Use hydraulic cement or expanding foam to seal gaps around pipes.
4. Clear Vegetation: Keep grass and bushes trimmed back from the foundation to remove cover.

If you suspect you already have guests, call Critter Removal of Louisville. We can perform a search, remove any residents, and seal the house properly so you remain the only one living there.