A case of mistaken identity: Big snail is beneficial, not bad

Typical rosy wolf snail Typical rosy wolf snail Image 1 of / 6 Caption Close A case of mistaken identity: Big snail is beneficial, not bad 1 / 6 Back to Gallery

A case of mistaken identity sparked a false alarm this week when word spread that the giant African snail - a voracious mollusk that poses a potential health threat to humans - had come to town.

Turns out the big snail found in a Houston garden is beneficial, not bad. It was a rosy wolf snail, a predator of snails that devour garden plants, said Michael Warriner, invertebrate biologist with Texas Parks and Wildlife Department.

The good snail's story, like that of the bad snail's, seems like science fiction. But it comes with a happy ending.

Photos of the suspicious snail tipped Warriner to its identity. Both the rosy wolf snail and the giant African snail have appendices for seeing and smelling. But the rosy wolf snail has a third set, oral lappets, that help it locate other snails' slime. It then grabs its prey and rasps it with its radula, which works like a rough tongue, Warriner explained

In addition to its extra appendices, the rosy wolf snail matures to 2 or 3 inches, considerably smaller than the potentially 8-inch giant African snail, Warriner said.

"It's not uncommon for the rosy wolf to be mistaken for the giant African snail," said Tanya Espinosa, public affairs specialist at U.S. Department of Agriculture.

Without proper identification in this case, panic spread.

"We had people sending photos of snails," Espinosa said. "But as of now, there's no reason to believe the giant African snail is in Texas."

"However, it is fantastic people are alerting local and state officials when they see something suspicious," she said. "That's how it works, what it's set up for."

The giant African snail is considered one of the most destructive snails and a serious threat to crops. It's known to eat 500 plant species. It can also carry rat lungworm, a parasitic nematode that causes meningitis, the Centers for Disease Control and Prevention reports. The snail's slime also can transmit the parasite.

The African snail has been a problem in Florida, where the state agriculture department has collected more than 100,000 in the past two years.

Two other large but harmless snails in Houston-area gardens may be mistaken for the more dangerous giant African: the island apple snail and the channeled apple snail, said Autumn Smith-Herron of the Institute for the Study of Invasive Species at Sam Houston State University.

Another telling difference: The apple snails are aquatic while the giant African snails and rosy wolf snails are terrestrial, Warriner said.

Espinosa suggests scooping any suspicious large snail into a container with a lid, then notifying officials. But avoid handling it until it's identified.

Anyone who sees an unusually large snail should contact Stuart Kuehn of the U.S. Department of Agriculture's animal and plant health inspection service in Austin at 512-916-5241. Photos may be sent to stuart.w.kuehn@aphis.usda.gov.

Photos also can be sent to Warriner at michael.warriner@tpwd.state.tx.us.

More information is available at tsusinvasives.org, aphis.usda.gov and molluskman.com/Euglandina_rosea.html.