- José H. Leal
One Tree Snail Gone, a Big Loss to Planet Earth
This past week the digital media was abuzz with news of the passing of George, the tree snail. George was the last surviving Achatinella apexfulva, a species of Hawaiian tree snail that had been extinct in its natural habitat for many years. George, who passed on New Year's Day at an old 14 years of age, was the offspring of captive breeding, part of conservation efforts put in place in Hawai‘i to save the last few surviving species of island land snails. George’s caretakers had hoped to find a partner for him/her (most land snails are hermaphroditic, having both male and female reproductive systems), thus hoping to foster a critical mass of individuals and eventually reintroduce the species in the wild. The demise of Achatinella apexfulva is the latest in a long series of island snail extinctions, most triggered by the introduction of the mollusk-eating Rosy Wolf Snail, Euglandina rosea, from Florida to Pacific island groups, chiefly to Hawai‘i. The Rosy Wolf Snail was originally introduced into Hawai‘i in a failed attempt to purge the islands of another invasive mollusk, the Giant African Snail, Lyssachatina fulica, a species unintentionally introduced via the agricultural trade. Sadly, and ironically, the Rosy Wolf Snail immediately took a liking for a multitude of species of native snails, leaving the Giant African Snail alone. About 90% of the 750 species of Hawaiian land snails have undergone extinction in historical times, and many others are endangered. A large part of these extinctions have been caused by the introduction of the Rosy Wolf Snail. One could say that biological control never fails to fail.
[Achatinella apexfulva, shell from Waianae, Oahu, Hawai‘i, 1962, BMSM 115879; shell length = 17.1 mm, or 0.67 inch.] George was a member of the Achatinellidae, a family of small- to medium-size tree snails that has been severely affected in Hawai‘i and other Pacific Islands by the Rosy Wolf Snail. Its demise may not mean much to most, but may be seen by some as emblematic of the sad (and irreversible) consequences of humans tampering with the delicate balance of the biosphere. On the bright side, critically endangered species of the Achatinellidae and others are being kept in captivity by the State of Hawai‘i’s Snail Extinction Prevention Program, in an effort to stop or curtail their demise. The program, along with other organizations, including the Bishop Museum, the University of Hawai‘i, and the US Army, also provides habitat protection for snails facing extinction. Read more about George in this original article in Honolulu Magazine. Photo of the living snail courtesy Aaron K. Yoshino, Honolulu Magazine.