Gecko, Monito

Sphaerodactylus micropithecus

phylum: Chordata

class: Reptilia

order: Sauria

family: Gekkonidae

status: Endangered, IUCN Endangered, ESA

range: Commonwealth of Puerto Rico

Description and biology

The Monito gecko is a tiny lizard that grows to be about 1.5 inches (4 centimeters) long from tail to snout. It has a flattened body covered in mottled dark brown or gray scales. Its tail is tan. The Monito gecko has short limbs, each equipped with tiny suction cups for climbing around on cliffs. Its bulging eyes are protected by transparent scales. Monito geckos are quite vocal—they croak, bark, squeak, and make clicking noises.

Monito geckos are nocturnal (active at night). They eat an assortment of insects, including beetles, flies, crickets, spiders, and ants. Eating is generally done in groups. No studies have been done on their life cycles, so information is limited. Scientists do know that their mating season is from March to November. A Monito gecko in the wild probably lives from four to ten years.

Habitat and current distribution

Monito geckos can be found only in the Commonwealth of Puerto Rico on Monito Island, a small island located 3 miles (5 kilometers) northwest of Mona Island in the Mona Passage midway between Puerto Rico and the Dominican Republic. A thorough two-day survey of Monito Island in 1982 turned up about 18 of these geckos. Although wildlife biologists (people who study living organisms) do not know the population of the Monito gecko, it is probably somewhat higher than the 18 that were found in the survey.

Monito Island is surrounded on all sides by 100- to 150-foot cliffs. The top of the island is flat and composed of limestone (a form of rock) covered in cacti, shrubs, and stunted trees that manage to grow through cracks in the limestone. When the island was surveyed for Monito geckos in 1982, they were found only in two small areas. The places where they were found, though, did not seem to differ from other parts of the island.

History and conservation measures

Although geckos of a different species on nearby Mona Island are abundant and well known, the Monito gecko was not discovered until 1974. At that time, scientists found one adult male and one egg on Monito Island. They hatched the egg in a laboratory and then released the animals on the island. Until 1982, no Monito geckos were found, even when the island was surveyed. Then 18 were found in 1982. By all indications, this has long been a very rare animal.

Black rats, introduced to Monito Island decades ago, have probably been responsible for the very low population of the species. Because the population is so dangerously low, the entire area of Monito Island has been designated as critical habitat (area necessary for the protection and preservation of a species that has been listed under the Endangered Species Act. Critical habitat designation does not create a wildlife refuge or eliminate human activities in the area.)

The U.S. Fish and Wildlife Service recommends a complete biological study of the Monito gecko for future recovery plans.