Virgin Islands Boa Reintroduction

To breed and reintroduce Virgin Islands boas into their former range in the U.S. Virgin Islands


Virgin Islands boas, Epicrates monensis, have a long history of decline and extinction, primarily caused by agriculture development (primarily sugar cane) and the introduction of the black rat (Rattus rattus), the Norvegian rat (Rattus norvegicus), and the house cat (Felis silvestris f. catus) to the islands east of Puerto Rico (including Cayo Diablo, Eastern St. Thomas, Tortola, Guana, Greater Camanoe, Necker Cay, and Virgin Gorda), where the boas occur or occurred. High densities of the introduced Indian mongoose (Herpestes auropunctatus) on St. Thomas, St. John, Tortola, and Jost Van Dyke probably also contributed to the population decline of this tree boa. Island inhabitants also often kill any snakes they encounter. Local extinctions may also be linked to climatological shifts of the Puerto Rican Bank, causing inundations from the ocean and storms in the small uninhabited cays and islets where much of the boa population is now concentrated. New constructions on St. Thomas also threaten that small population.


The project, launched in 1984, began with a long term ecological study of Epicrates monensis. The nformation gained allowed to identify several sites suitable for reintroduction within the historical range of the boa, and exotic mammal eradication programs were implemented. Virgin Islands boas were reintroduced in a Puerto Rico site in 1993-94, and in a site in the U.S. Virgin Islands from 1996 to 2002. An evaluation of the Puerto Rico site, performed in 2003, indicated that the population had increased from the 41 released captive- born snakes to approximately 500 snakes. No boas were present on the site before the reintroduction. In the U.S. Virgin islands, an evaluation performed in 2004 demonstrated that the initial population of 42 boas -including both translocated and captive-born snakes - had increased to approximately 170 snakes. Current activities focus on identification and evaluation of additional sites suitable for reintroduction, rat eradication, and breeding of additional snakes for release. The conservation breeding program is cooperatively conducted by the American Zoo and the Aquarium Association’s Mona/ Virgin Islands Boa Species Survival Plan.


WAZA Conservation Project 05036 is implemented by the Toledo Zoo and the American Zoo and Aquarium Association in cooperation with the Departamento de Recursos Naturales y Ambientales de Puerto Rico, Division of Wildlife, U.S. Virgin Islands, U.S. Fish and Wildlife Service.  


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