The prohibited snails arrived from Nigeria and were being sent to a person in San Dimas, said Lee Harty, a spokeswoman for the U.S. Customs and Border Protection.
Officials said the customs officials received notification of the snails on July 7. They were confiscated on July 1 and a sample was sent the next day to a mollusk specialist at the U.S. Department of Agriculture in Washington, D.C., who identified them as a prohibited species, Harty said.
Officials said the mollusks are among the largest land snails in the world and can grow to be up to 8 inches long. They are native to Africa and can live for up to 10 years.
The USDA incinerated the snails after they were inspected, Harty said. Officials said the snails are prohibited in the U.S. because they can carry parasites that are harmful to humans, including one that can lead to meningitis.
The snails are also agricultural pests, said Maveeda Mirza, the CBP program manager for agriculture.
"These snails are seriously harmful to local plants because they will eat any kind of crop they can get to," Mirza said.
The person who the snails were destined for is not expected to face any penalties, Mirza said. She said authorities are investigating why a single person would want so many snails.
"We're investigating what happened but it doesn't seem like there was smuggling involved. When someone doesn't know a commodity is prohibited under USDA regulations there is usually no punishment," she said.
Although the agency has found one or two snails that may have accidentally gotten into a traveler's luggage in Los Angeles, this is the first time that they have confiscated the snails in such a large quantity, Mirza said.