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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

  • Taxon: Reptile
  • Range: Monito Island, Puerto Rico
  • Status: Delisted due to recovery

The Monito gecko, a tiny lizard that lives only on Monito Island off the west coast of Puerto Rico, was listed as endangered in 1982 due to an influx of black rats, a non-native omnivore that preyed upon the species throughout its range. In 1992, Puerto Rico Department of Natural and Environmental Resources (PRDNER) began a black rat eradication project on Monito Island and the agency mounted a second eradication initiative in 1999. Thanks to these efforts, and assistance from a variety of other conservation partners, black rats have been officially eradicated from the island. There are now an estimated 5,000 -11,000 geckos on Monito Island.

On October 3, 2019, the Service removed the Monito gecko from the List of Threatened and Endangered Wildlife under the Endangered Species Act due to recovery. The gecko is now so abundant that it no longer warrants protection under the Endangered Species Act thanks to the effective conservation partnership between the Service and the PRDNER that successfully removed the gecko’s main threat and continues to protect the resilient lizard and its habitat.

Download the Monito gecko fact sheet, or the post-delisting monitoring plan.


Appearance

The Monito gecko is the only species of the Sphaerodactylus genus found on Monito Island. It is a tiny reptile, usually measuring an inch and a half (3.5 centimeters) long. It has a pale-tan body and dark-brown mottling on it’s back, a dark brown tail, and can have two dark patches with a white dot on its neck.

Habitat

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.

Diet

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 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 Monito gecko. 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, 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.

Recovery from endangered status

The Monito gecko has improved in status due to the active partnerships of many private landowners, state and Federal agencies, universities, and non-governmental organizations Thanks to an effective conservation partnership between the Service and the PRDNER, the Monito gecko is now so abundant that it no longer warrants protection under the Endangered Species Act. On October 3, 2019, the Service removed the Monito gecko from the List of Threatened and Endangered Wildlife due to successful recovery.

A post-delisting monitoring plan is in place to ensure the population’s long-term viability. The plan summarizes the species’ current status, defines thresholds for potential monitoring outcomes and conclusions, outlines reporting procedures and responsibilities, and other conservation actions. Post-delisting monitoring will be completed through the cooperative efforts of the Service, PRDNER, and other partners.

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
fws.gov/caribbean

Designated critical habitat

The Monito gecko was removed from the endangered species list due to recovery. The species no longer has designated critical habitat.

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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