Puerto Rican Boa

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Puerto Rican Boa

Epicrates inornatus

ListedOctober 13, 1970
FamilyBoidae (Constrictor)
DescriptionLarge, muscular snake; tan to dark brown with diffuse, irregular markings.
FoodCarnivorous; birds, mice, lizards, bats.
RangePuerto Rico


The Puerto Rican boa is the largest snake found in Puerto Rico, measuring up to 7.3 ft (2.2 m) in length. Color ranges from tan to dark brown. Patterning often consists of 70-80 irregular, diffuse markings along the back, but some snakes are uniformly dark. Underside scales are dark brown with pale edges. Juveniles are reddish brown with prominent markings; females are larger than males.

The Puerto Rican boa can be distinguished from its relative, the Mona boa (Epicrates monensis ) of Mona and the Virgin Islands, by its larger size and darker coloration.


The Puerto Rican boa is most active at night, during the day it basks in the sun or remains concealed in trees or caves. It feeds on birds, mice, rats, and lizards and is known to prey on bats. A boa will suspend itself from a branch near a cave entrance and seize bats as they emerge. The Puerto Rican boa, like others of its family, is ovoviviparous. Eggs hatch within the mother's body, and the young are born alive. Evidence suggests that it mates between February and April and gives birth in September or October. Boas typically reach sexual maturity after six or seven years.


The Puerto Rican boa is at home in a wide range of habitats. It is most common in northern Puerto Rico in a band that extends from Aguadilla on the western coast east to San Juan. This is a region of limestone karst topography, characterized by "haystack hills" and sinkholes. Hills support dry open forests, while sinkholes support a lush moist growth. These combined habitats produce a great variety of wildlife and an abundance of prey. Habitat elevation ranges from sea level to about 1,300 ft (396 m).


The Puerto Rican boa appears to range throughout the island but is more common in the north. The snake's nocturnal habits have inhibited systematic research. But available data suggests that the population declined dramatically during the first half of the twentieth century, going from relative abundance to relative scarcity. This decline was blamed on widespread deforestation of the island. Between the mid-1980s and the mid-1990s, however, many acres of former agricultural land have been abandoned, and the forests are returning. About 40% of the island is currently forested. As a result, the Puerto Rican boa population appears to be increasing.


Habitat loss, intensive hunting for its food and oil, and predation by exotic mammals, especially cats and mongoose, were the probable causes for decline. Historic records indicate that this species was quite abundant during the first three centuries of Spanish colonization. Increased deforestation to clear land for agricultural and industrial use destroyed much of the snake's essential habitat. Populations have generally increased when cleared land has been allowed to revert to native forest.

Conservation and Recovery

Because exact population figures are not known, patterns of decline and recovery are difficult to measure. The U. S. Fish and Wildlife Service Puerto Rican Boa Recovery Plan establishes long-term research goals to answer questions about density and distribution, locate unknown populations, determine habitat preferences, and delineate limiting factors. The first phase of this research was scheduled for completion during the early 1990s after which quantifiable recovery goals could be set. The Puerto Rican boa is protected from collecting and hunting by the commonwealth of Puerto Rico's Wildlife and Hunting Regulations of 1978. In 1985 the boa was listed as Endangered under Puerto Rico's Regulation to Govern the Management of Threatened and Endangered Species.


Regional Office of Endangered Species
U.S. Fish and Wildlife Service
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345

Boqueron Ecological Services Field Office
U.S. Fish and Wildlife Service
P.O. Box 491
Boqueron, Puerto Rico 00622-0491
Telephone: (787) 851-7297
Fax: (787) 851-7440


Reagan, D. P. and C. P Zucca. 1984. "Ecology of the Puerto Rican Boa in the Luquillo Mountains of Puerto Rico." Caribbean Journal of Science 20:3-4.

Rodriguez, G. A., and D. P. Reagan. 1984. "Bat Predation by the Puerto Rican Boa, Epicrates inornatus." Copeia (1)219:220.

Tolson, P. K. 1984. "The Ecology of the Boid Genus Epicrates in the West Indies." In 5to. Simposio de Ecologia. Universidad del Turabo, Caguas, Puerto Rico.

U.S. Fish and Wildlife Service. 1986. "Recovery Plan for the Puerto Rican Boa." U.S. Fish and Wildlife Service, Atlanta.

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