Striking New Snake Species Found in the Bahamas

Silver-Boa
The elegant newfound species, the Conception Bank silver boa (Chilabothrus argentum), was found on a tiny island in the Bahamas. R. Graham Reynolds

Records of reptilian life in the Bahamas go back to the days of Christopher Columbus, who described the lizards and sea turtles of the region when he landed on several of these islands in 1492. He noted, for example, that rock iguanas were a favorite food of the native Lucayan people.

And yet the islands still hold biological secrets. Scientists have now made a startling discovery on a small, uninhabited isle called Conception in the Bahamas: a new species of boa constrictor.

As described in a study published in the journal Brevoria, scientists were studying the genetics of lizards on the island when they happened upon a striking silver snake in July 2015.

“As soon as we saw it we knew it was something unique,” says Graham Reynolds, a herpetologist at the University of North Carolina-Asheville.

The researchers named the new species the Conception Bank silver boa (Chilabothrus argentum). The handsome serpent has a silver coloring, grows to a maximum length of 3 feet and weighs less than 1 pound. Unlike most other West Indie boas, of which there are 12 species, the Conception Bank species tends to only hang out in trees where it feeds exclusively on birds. It uses muscles in its body to crush the birds to death before eating them, Reynolds says.

silver-boa-bird This young silver boa tried to eat a bird called a Cape May warbler, but missed, and came away with only feathers. R. Graham Reynolds

It's quite rare to find a new species of snake that is not only genetically distinct, but looks unlike anything seen before, Reynolds says. And nobody had identified a new snake in the West Indies for 73 years prior to this find, according to the study.

Reynolds and colleagues took bits of the animals’ scales and genetically analyzed them at Harvard University, where Reynolds was a postdoctoral fellow at the time. They found that these snakes diverged from others in its genus (the taxonomic grouping above species) about 2 million years ago, Reynolds says. Its common ancestor hails from Hispaniola, meaning that this snake island-hopped its way to Conception over the years, a distance of more than 350 miles.

Unfortunately, the researchers have also classified the snake as critically endangered, under conditions set forth by the International Union for Conservation of Nature. The scientists found a total of six snakes on their first visit, and after three subsequent trips have only turned up a total of 33 individuals.

Reynolds and his colleagues have also found the pawprints of feral cats on the island. That’s very bad news for the boas, since cats are known to eat these small, docile snakes. Fortunately, the island is uninhabited and part of the Bahamas national park system.

silver-boa-head The silver boa reaches a maximum length of just over 3 feet and weighs under 1 pound. R. Graham Reynolds

Bob Henderson, a curator emeritus of herpetology at the Milwaukee Public Museum who wasn’t involved in the research, says he’s worried that collectors will target the small island to find these animals. In fact, he’s certain that it will happen, as it has when other rare lizards and snakes have been discovered elsewhere. He says he hopes that the Bahamas National Trust, which is in charge of the island, will help prevent this from happening. The researchers avoided saying exactly where they found the snakes, but the island is only three square miles (just over twice the size of New York’s Central Park).  

The team will soon return to the island with camera traps to prove that feral cats are there, and they plan on submitting that information to the trust. Reynolds hopes the organization will take measures to remove the cats, which “don’t belong on the island” and threaten the snake’s continued survival, he adds.  

"It just shows you that wonderful new things can be discovered today," Henderson says. "The age of exciting discoveries is not in the past."