We were stopped in our tracks the other day when a Rosy Wolf Snail crossed our path. This very long snail (3″ or so?) is a predator of other snails and slugs and it’s native to the southeastern United States.
A cannibal snail
As a predator of other snails and slugs, the snail might make the local gardener happy. Each one can eat up to 350 other snails and slugs during its lifetime! They move quite quickly (one study said they could go in short bursts of up to 19 mph!) And they can swallow other snails and slugs whole! If the prey is too large, they can squeeze their long proboscis into a snail shell and drag it out. Their third appendages, which are really modified lips, allow them to taste the ground to follow the trails left by other snails and slugs. (This is how they got their name; following scent like a wolf.) They’ll even prey on other Rosy Wolf Snails.
Adaptations for living on land
I thought it was really interesting to find out that these snails have developed a rudimentary lung system to allow them to live life on land. Moon snails breathe with gills. Land snails have also evolved to have eyes on tall stalks so they can see over grass and things in their way, and all of their tentacles can retract. Moon snails have tentacles, (see photo) but they can’t retract them independently~ when the snail retreats into its shell, everything retracts at once.
Rosy Wolf Snails aren't Welcome Everywhere
The Giant African Land Snail is an invasive pest that originally arrived in the US (Hawaii) in the 1930’s. It’s so big that people raise them as pets and food, as well as “garden ornamentation.” The snail got quickly out of control and consumed crops as well as other snails. To try to control it, Rosy Wolf snails were brought in– after all, they’re a “natural predator.” But the law of unintended consequences crept in, and the voracious wolf snails have contributed to the extinction of other snail species in Hawaii and Tahiti. Now, scientists want to understand how habitat gives these snails an advantage, so they have glued tiny computers to their shells to compare them to endangered local snails.