A recent study showed that the San Francisco International Airport could be housing more than 1,000 snakes.

In a study commissioned by the U.S. Geological Survey and the U.S. Fish & Wildlife Service, researchers found that more than 1,300 snakes live on the airport’s West-of-Bayshore property. The area is a 180-acre undeveloped parcel of wetlands and uplands.

The study found that the area, which is off-limits to the public, houses the populations of two endangered animal species, such as the San Francisco garter snake and the California red-legged frog. 

An estimate by the researchers put the snake population at the site at approximately 1,300, making it the largest known concentration of any location.

The same San Francisco International Airport is also home to grazing goats.