In Florida, scientists have discovered a surprising range of wildlife living in underground stormwater sewer systems—including alligators.
A recent study in Alachua County found that many animals, including raccoons, bats, and reptiles, use these tunnels to move around as cities expand and natural spaces shrink. Researchers placed cameras in several locations to track how different species interact with these underground passageways.
Unlike regular sewage systems, which carry waste, stormwater sewers are designed to redirect rainwater away from roads and buildings. Between February and May 2023, the cameras captured over 3,700 animals from 35 species, including amphibians, reptiles, and birds. Alligators were the most frequently spotted reptiles, appearing at five different sites.
“I expected to see rats,” said researcher Alan Ivory from the University of Florida. “But I didn’t expect to see raccoons with their babies or alligators hunting fish.” Most of the animals found were mammals, with raccoons and Southeastern myotis bats making up more than half of all sightings.
Scientists learned that animals use these underground tunnels in different ways. Some treat them like highways, traveling between ponds, while others use them for shelter, raising young, or finding food. Small reptiles and amphibians, like frogs and snakes, often end up in the system by accident, swept in by heavy rain.
The researchers hope their findings will help prevent animals from getting trapped in these tunnels and inspire further studies in other areas.
