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A small, sand-colored reptile between the cracks of a rock
Information icon Monito gecko. Photo by Jan Paul Zegarra, USFWS.

Monito gecko

Sphaerodactylus micropithecus


The Monito gecko is the only species of the Sphaerodactylus genus found on Monito Island off the coast of Puerto Rico. It is a tiny reptile, usually measuring an inch and a half (3.5 centimeters) long. It has a gray body, a dark brown tail, and has two dark patches with a white dot on its neck.

Not much is known about the reproductive biology of this species, but it is believed their breeding season lasts from March through November. The population is currently estimated to have more than 7,000 individuals.

Download the Monito gecko fact sheet.


The gecko can be found on the ground, mostly hiding during the day within leaf litter and debris, and small crevasses and holes in the karst rock of Monito Island.

A small, rocky, vegetated island with mainland Puerto Rico in the distance
Monito Island is an uninhabited and mostly inaccessible island of only about 36 acres. It lies west of Puerto Rico and was designated a U.S. National Natural Landmark in 1975. Photo by USFWS.


It is assumed the geckos feed on small invertebrates such as insects and spiders. However, there is no specific information regarding their feeding habits.

Current range

This gecko is only found in Monito Island. This island is part of the Mona and Monito Islands Nature Reserve of Puerto Rico managed by the Puerto Rico Department of Natural and Environmental Resources (PRDNER). Monito Island is located about 50 miles (80 km) west of Puerto Rico’s mainland and 3 miles (5 km) northwest of Mona Island. Both islands are located between Puerto Rico and the Dominican Republic.

A map showing Monito Island off the west coast of mainland Puerto Rico
Monito Island off the western coast of Puerto Rico. Map by Roy Hewitt, USFWS.

Conservation challenges

The destruction and modification of habitat by humans, and the previous occurrence of introduced rats to Monito Island, represent the biggest threats to the species.

Recovery plan

Due to controlled access to Monito Island and other protective measures set in place by the PRDNER, threats have been reduced. The PRDNER implemented a rat eradication program on Monito, and the island has been rat free since late 1999. Visitors are forbidden from visiting Monito Island without authorization, and it is given only to scientific research-related projects.

Download the five year review (2016), or the recovery plan (1986).

Subject matter experts

Caribbean Ecological Services Field Office
Address: PO Box 491, Boquerón, PR 00622
Telephone: 787-851-7297 / Fax: 787-851-7440

Designated critical habitat

Monito Island is designated as Critical Habitat for the Monito gecko.

Federal Register notices

The following Federal Register documents were automatically gathered by searching the Federal Register Official API with this species’ scientific name ordered by relevance. You can conduct your own search on the Federal Register website.

  • We're sorry but an error occurred. Visit the Federal Register to conduct your own search.

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