Friday, February 7, 2014

Giant African Snails returning to Florida

It's time for an update to Giant African Snails invading Latin America.  These animals have now returned to Florida after an earlier invasion was repelled.  Matt Simon of Wired tells the story of both invasions in Absurd Creature of the Week: Foot-Long, Sex-Crazed Snails That Pierce Tires and Devour Houses
Ah, the innocence of children. So free of corruption and cynicism, so sweet and sincere. Laughing and playing and introducing supremely destructive monster snails to Florida, where the beasts eat almost anything that’s green and then crap all over houses — quite literally laying waste to whole neighborhoods.

This actually happened in the 1960s, when a boy vacationing with his family in Hawaii had pocketed a few giant African land snails (Lissachatina fulica), a mollusk that grows to a foot long and a full pound. Hawaii had been battling the pest, and so too would Florida, where the boy returned with his new friends. Once home, he quickly grew bored of the snails and handed them over to his grandmother, who set them free in her backyard.

What ensued was an invasion by rapidly reproducing critters that have over the last century spread out of their native East Africa into tropical climes all over the world, from Asia to South America, as stowaways on ships or as pets brought home by people with a thing for snails. In Florida, eradication took seven years. Other places, like Brazil, have not been so lucky in their efforts.
At least the first invasion had a happy ending for Florida, if not for the snails.  Follow over the jump for the tale of the second invasion.

Wired reports that the second successful introduction is only three years old, but it appears to be even more severe.
Alas, four decades after evicting this enormous, fecund snail, Florida finds itself overrun once again. The creature was reintroduced here in 2011, and this time, according to Cowie, it may well be “bizarre, voodoo-like religious proceedings” to blame. The snail’s slime, he says, is coveted in certain South American rituals, and practitioners may have released the giant snails into their Miami-area backyards, hoping they’d breed freely.

The USDA and U.S. District Attorney’s Office are investigating this. It probably doesn’t help the ritualists’ case, though, that the year before the current outbreak, authorities questioned a Florida man said to have convinced his followers to drink the fluid from live giant African land snails, which he sliced open before squeezing the slime into their mouths. If you can believe it, the victims fell violently ill — ironic, what with this being a healing ritual.

Anyway, if it was indeed the practitioners who released the snails so they (the snails, not the practitioners) could multiply rapidly, it worked. Big time. Florida agriculture officials have collected 137,000 giant snails in just over two years. Compare that to the relatively few 17,000 collected in the first eradication in the 1960s, and you soon see the magnitude of this problem.
So, what do these snails do that makes them such pests?  Gizmodo has the answer in What's Eating Florida? These Six Voracious Species.
Giant African Land Snails, or G.A.L.S (technically, Lissachatina fulica) live up to their name. Native to Kenya and Tanzania, these monopods are obscenely huge and, the problem is, they've got sex drives and appetites to match.

GALS were initially imported to Florida in 1966 from Hawaii, and have since experienced a population explosion—thanks to their ability to digest over 500 species of local plants and their ability to lay upwards of 200 eggs a year (they're also hermaphroditic). Adults can measure over a foot long and tip the scales at more than a pound, making them an enticing prize for exotic pet owners. But in the wild, they're a dangerous pest, out-competing native species for resources and destroying property. GALS have developed a taste for calcium-rich stucco siding, which the snails use to produce their massive shells, and have been known to puncture car tires with their probosces in search of a meal.

Thanks to a concerted effort by the Florida Agricultural Commission—employing specially trained sniffer dogs, bait traps, and community involvement—the snail's days appear numbered.
This video is part of that campaign by the Florida Agricultural Commission.

This is a 30-second advertisement created for a movie theater audience about the giant African land snail in Miami, Florida.
As I've mentioned before, I tell my students about the unsuccessful attempt to control these animals in Hawaii.  Wired wrote about that, too.
[Biologist Robert] Cowie [of the University of Hawaii] knows all too well the explosive population growth these things are capable of when left unchecked. In Hawaii, where he lives, the giant African land snail was introduced in the 1930s by Japanese immigrants who wanted to keep them as pets. They have since essentially assumed ecological control, tearing through agriculture and muscling out native species.

In 1950s Hawaii, “there were stories of on a rainy day, when the snails all came out and crawled all over the road,” Cowie said, “the cars would squish them and cars would end up skidding on the squished snail. Dead, crushed snail and slime, sort of all mish-mashed together by the cars. So that was when Hawaii got serious about trying to control them. And we’ve not been successful at controlling them.”
I can hear my students saying "Ew" when I add these details to the story the next time I tell it.


  1. Replies
    1. They're OK eating. They're a bit on the tough and gritty side and they have to be thoroughly cooked so that any parasites, such as the rat brainworm described in the Wired article, don't get transmitted. That written, slather them in enough butter and garlic and you can hardly tell them from regular escargot snails.