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Native and Invasive Land Snails

Predators, like Florida’s Rosy Wolf Snail, were introduced to many Pacific islands to control invasive snails such as the Giant African Snail. Unfortunately, these introductions had no impact on the invasive target species, and instead devastated the native snail populations.

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Native and Invasive Land Snails by John Slapcinsky

More than half of all animal extinctions recorded in the past 500 years have been of mollusks, particularly snails and clams. The majority of these extinctions have been land snails from Pacific Islands and are the result of habitat loss the introduction of predators to isolated island groups.

One of the most infamous examples of this is the introduction of Florida’s Rosy Wolf Snail, a predator of other snails, brought from Florida to the Hawaiian Islands to try and control populations of the Giant African Snail that had been accidentally brought to Hawaii in the 1940s. The Giant African Snail quickly became an abundant and serious agricultural pest prompting efforts to control its populations, including the introduction of the Rosy Wolf Snail. Unfortunately, the 2-inch-long predator preferred the small native species to the much larger agricultural pest and populations of native snails quickly declined, resulting in the loss of more than half of Hawaii’s native snails and leaving most of the rest on the brink of extinction. The Wolf Snail was later introduced to many other Pacific islands in similar control efforts. The Hawaiian Islands were home to more than 850 different land snail species, only a little less than the 1100 snails found in the mainland of the U.S., but in a much smaller area. This episode is probably the single-most catastrophic extinction event in modern times.

John Slapcinsky
Collection Manager, Invertebrate Zoology
Florida Museum of Natural History