Updates and Information on Coronavirus (COVID-19)
Skip to main content

KNOXVILLE, Tenn. — Giant African snails sold in some Tennessee pet shops could damage crops if released into the wild, University of Tennessee scientists said Wednesday.

Dr. Gary McCracken, a UT-Knoxville zoologist, said some of the giant snails, imported illegally from Nigeria, can grow almost as big as a football.

The snails eat more than a quarter of their body weight daily, and one adult snail could probably eat an entire head of lettuce or cabbage overnight, he said.

The U.S. Department of Agriculture estimates that 1,000 giant snails have been shipped to 25 states. Bob Milam, of the USDA plant protection and quarantine office in Nashville, said about 30 snails are known to have been shipped to Tennessee. Twenty of them have been found in pet shops in Memphis and Nashville, he said.

An infestation by a similar giant snail in Florida cost $10 million to remedy, Milam said.

”They cause the most trouble when they first come into an area,” McCracken said. ”When introduced into a new area, they experience explosive growth and cause maximum crop damage.”

After a few months, the snails would probably begin falling to local predators and pathogens, and settle down into more of a chronic-type problem, McCracken said.

McCracken, a specialist in exotic animals who has studied snail species, said snails have a type of natural ”anti-freeze” in their blood, which would help the African snails survive Tennessee’s colder winters. The added moisture, foliage and agriculture here also could create good conditions for the snail’s survival, he said. The snails live under logs or rocks in the winter, and reproduce rapidly, he said.

”If some of these snails are brought in, find favorable conditions, and have a population explosion, they could be devastating to people trying to grow things,” said Dr. Harry Williams, plant pathologist with the UT Agricultural Extension Service.

Williams said snails and slugs in Tennessee thrive in moist, damp, or shady conditions. They can be a problem in greenhouses, mulched areas, and around debris such as old boards and logs.

Tennessee crops most damaged by snails are strawberries, ornamental plants and flowers such as orchids, and leafy vegetables like cabbage and lettuce, Williams said. They are particularly troublesome to growers because they eat a wide variety of plants, feed year-round, and only come out at night, Williams said.