Unwanted Visitors: California Kingsnakes Are Overwhelming This Spanish Island

Native wildlife and pets have no defense against the invading reptiles, which came to Gran Canaria as pets.

(Photo: Chanel Beck/Flickr)

May 8, 2014· 1 MIN READ
John R. Platt covers the environment, wildlife, and technology and for TakePart, Scientific American, Audubon, and other publications.

Thousands of five-foot-long albino snakes from the U.S. have wreaked havoc on the tiny Spanish island of Gran Canaria. The California kingsnakes, which came to the island decades ago through the pet trade, face no natural predators in their new home. Experts fear that some species of birds, rodents, and rabbits that are native to Gran Canaria might go extinct if the invading snakes are not stopped.

The problem is so severe that a group of international experts is traveling this week to Gran Canaria to advise local officials on ways to eradicate the snakes. One method on the table: using massive earth movers to plow up infected areas where the snakes may be resting belowground.

Until then, officials will continue to rely on dogs and trained hawks to kill the snakes. But it's not an easy task. The species spends most of its time underground, where it can't be easily found.

"The fact that you're removing hundreds of visible snakes means, unfortunately, that it is likely that there are many, many thousands more out there you can't see," Robert Reed, an invasive species specialist for the U.S. Geological Survey told the Los Angeles Times last month.

Even pets are not safe from the invaders, which have adapted so well to Gran Canaria that they have grown 30 percent larger than normal. While the reptiles have even been known to bite humans, they're not venomous, and no serious injuries have been reported.

Not all the California kingsnakes on Gran Canaria are albinos; some also have been observed with stripes and bands, as the animals are selectively bred in the pet trade for their coloration. Experts say because albinos have done so well on the island, where they would not normally survive in nature, it is an indication of how well they have adapted to their new home.

The snakes are restricted to two small regions of the 602-square-mile island, but experts fear they could soon overwhelm up to 70 percent of it. A study conducted in 2011 by the IUCN Invasive Species Specialist Group supports this fear. First observed on the island in 1998, the snakes have expanded their territory each year. By 2011, they had taken over more than 3.5 percent of the island.

"If it gets any more out of control, it just will become a daunting and unforgiving task that will require a small army," Ramón Gallo, a biologist spearheading the eradication efforts, told The Guardian.