Wild Thing: Killer on the Prowl
The cannibalistic wolf snail lives up to its name.
By Ben Hutchins
It’s a damp spring morning in the Texas Hill Country, and as I walk to my car, I hear a crunch under my feet. Snails by the hundreds are taking advantage of the damp conditions to feed and reproduce.
These little mollusks have far more to fear than my careless steps, because a killer is on their trail. Though snails are food for a variety of organisms, including birds, rodents and snakes, they are also a featured menu entrée for a cannibalistic cousin.
Wolf snails (genus Euglandina) specialize in hunting and devouring other snails and slugs. Using sensitive receptors on their tentacles, head and lips, wolf snails detect the slime trail left behind by a potential meal. Like their mammalian namesake, they then begin tracking their prey, hunting at a snail’s pace that is several times faster than the average snail. Once it finds its prey, the wolf snail will begin to devour the other snail alive, swallowing it whole or cutting off bits of flesh with an array of specialized teeth called radula. If necessary, wolf snails are capable of rolling their victim over and using their elongated body to get inside the would-be protective shell. There’s no escape!
Wolf snails are some of Texas’ largest land snails. The smallest of Texas’ three wolf snail species, the glossy wolf snail (Euglandina texasiana), occurs only in the lower Rio Grande Valley and adjacent portions of northern Mexico. The striate wolf snail (Euglandina singleyana), native to much of the Edwards Plateau and parts of the Gulf Coastal Plain, has a shell over 2.5 inches in length. Even larger, the rosy wolf snail (Euglandina rosea), a native of the southeastern U.S. introduced to parts of coastal Texas, has a shell 3 inches long. These snails are so large that they have been mistaken for invasive giant African land snails, causing a wave of false alarms from the media in 2013.
Wolf snails are most readily found under fallen logs and rocks in wooded valleys and lowlands, but they may also be found under boards, ground-covering plants and rocks in gardens and urban green spaces. More often than not, only empty shells are found, as the adults seek shelter in secluded crevices to avoid drying out. As with many species of snails, your best chances of seeing a live wolf snail is during a cool, damp morning or at night, especially after a light, steady rain.
Although finding one of these large snails in your garden may be disconcerting, remember that they are hunting a variety of other slugs and snails that could be real pests for your plants. Enjoy the service provided by these voracious hunters, but avoid keeping them as pets and never transport them. The rosy wolf snail, in particular, has become an invasive terror, causing the extinction of many native snails around the world.
See more wildlife articles on TP&W magazine's Texas wildlife page