Boa Constrictors Spreading their Breeding Population in Puerto Rico: Report

Boa constrictors are increasingly establishing their breeding population in Puerto Rico, according to a report from the U.S. Geological Survey (USGS).

Boas are non-venomous constricting snakes that belong to the family of Boidae. These exotic snakes are native to Central and South America. They can grow more than 10 feet and weigh up to 35 pounds.

Until now, boas and two types of pythons are known to have established their invasive population in Florida. For the first time, researchers have documented the presence of non-native boas in a territory outside Florida. They found that the boas are slowly spreading their breeding population from its origin around the city of Mayagüez in Puerto Rico.

More than 150 boas have been found in the wild on the Puerto Rican island. Researchers presume that the boa constrictors might have likely originated from a small number of snakes that were released as pets in the early 1990s.

"Experience has shown that island ecosystems are particularly vulnerable to snake invasions, and unfortunately Puerto Rico has no natural predators that can keep the numbers of these prolific, snakes in check," USGS director Marcia McNutt said in a statement.

"Humans were responsible for introducing this scourge to the island, and are the only hope for mitigating the problem before it is too late for the native species," she said.

Based on a genetic study, experts have found that individual boas in the island are closely related to each other. They observed that two snakes located at some distance from the expanding Mayagüez population share genetic markers. This suggests that the snakes are involuntarily being moved to longer distances around the island.

This might increase the rate at which the invasive boa population could spread across Puerto Rico. Boas are very secretive and difficult to spot. This means that the population size of these reptiles could be more than what is being estimated, said the researchers.   

The findings of the study, "Genetic Analysis of a Novel Invasion of Puerto Rico by an Exotic Constricting Snake", are published in the journal Biological Invasions.