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A female frog on a tree branch. Photo by JP Zegarra, USFWS.

Puerto Rican rock frog or coquí guajón

Eleutherodactylus cooki

  • Taxon: Amphibian
  • Range: Southeastern Puerto Rico
  • Status: Threatened

The Puerto Rican rock frog is known by several names: Puerto Rican cave frog, guajón, and the Puerto Rican demon. It earned this name because many years ago, people thought its voice was that of an evil spirit in the forest.

Oddly for a frog, it sings mainly during the day while hidden within rocks and caves. At night it searches for food. The guajón is the second largest of the seventeen species of frog from the genus Eleutherodactylus, commonly known as “coquíes,” that inhabit Puerto Rico.

Coquíes in general are cherished in Puerto Rico. The sounds of singing males are a distinctive feature of the Puerto Rican landscape and a valued symbol of the island’s natural and cultural heritage.

Appearance

The guajón is a relatively large frog, approximately 8.5 centimeters (3.3 inches) in length.

Guajón females are larger than males with solid brown coloration on the dorsal area. They are uniformly white on the ventral area with white-rimmed eyes and large, truncate disks on the feet. Males have yellow coloration on the ventral area extending from the vocal sac to the abdomen and flanks.

The voice of the guajón is low and melodious.

A small peach-white frog
Guajón. Photo by Alberto Puente.

Habitat

The guajón is native to Puerto Rico and is restricted to the southeastern part of the island. It was previously believed to occur exclusively inside caves containing or adjacent to streams; however, habitat studies by Vega-Castillo (2000) showed that the guajón also lives in rocky streams.

Caves are dark inside, although some light enters through gaps formed from the union of two or more boulders of rock. Structurally the caves are complex, in the form of several chambers of irregular shape and size, and at different depths between the surface of the ground and stream. The ecological conditions of the caves are similar: mean temperature and relative humidity are the same at any given month of the year, and they do not have thermal stratification.

In streams, the species has been found only in patches of rock in the streambed. The streams are surrounded by secondary forest and can be a perennial, or an ephemeral stream, which forms with heavy rain. Rocks in the streambed form crevices and grottoes. Streams provide a wide variety of retreat sites for the species, such as vegetation over rocks (e.g., moss, ferns and liverworts) that help in the conservation of humidity. Temperature and relative humidity at streams vary within the year.

Range

The guajón occurs at low and intermediate elevations from 18 to 1,183 feet above sea level where they inhabit caves formed by large boulders of granite rock known as “guajonales” or streams with patches of rocks without cave systems.

The guajón is extremely restricted in geographical distribution and occurs only on privately-owned lands. See Designated Critical Habitat.

Conservation challenges

The guajón was listed primarily due to its highly restricted geographical distribution and habitat requirements. Being a habitat specialist, the guajón is adapted to particular environmental conditions, and abrupt changes in these conditions could result in population declines.

The destruction, modification, or curtailment of the species habitat or range continues to be an important factor threatening the survival and recovery of this species. The immediacy of this threat is high because the guajón’s habitat is naturally fragmented and the majority of the known populations are on private lands, where an increased level of land development may further reduce and fragment the species habitat, alter their distribution, and affect their chances of survival.

Amphibians are less adaptable than other animals to habitat changes because of physiological constraints. The maintenance of highly permeable, moist, cool skin that allows for efficient respiration generally requires habitats that are humid with low evaporation rate. In addition, small size and slow movement result in relatively poor dispersal capabilities and small home ranges. These physiological factors cause amphibians to be especially sensitive to the abrupt transitions impacting their microclimate and microhabitat (Demaynadier and Hunter 1998).

Recovery plan

The recovery criteria for the guajón are as follows:

  1. Permanently protect traditional, non-traditional, and unoccupied guajón habitat, and corridors between existing populations, through landowner agreements, conservation easements, habitat conservation plans, and public outreach.
  2. Determine the viability of existing populations (e.g., numbers, breeding success, population genetics, and ecology), and how many viable subpopulations are needed to ensure a self-sustaining overall population.
  3. Determine the geographic distribution of all subpopulations needed to ensure a self-sustaining overall population.
  4. Survey all potential habitats for new occurrences and evaluate suitability for species introduction.

For more information, download the complete Recovery Plan for the guajón.

Subject matter experts

For more information about this species, please contact:

U.S Fish and Wildlife Service
Caribbean Field Office
Boquerón, Puerto Rico
(787) 851-7297, extension 219.

Designated critical habitat

All of the units designated as critical habitat for the guajón are privately owned and adjacent to agricultural lands, roads, trails, homes, or other manmade structures.

Management considerations and protections include management of non-native predators, and protection of guajón and its habitat from threats by deforestation and earth movement near streams for road construction, agricultural, urban, and rural development that may result in changes in the composition and abundance of vegetation surrounding guajón habitat; and degradation of water quality from illegal garbage dumping, untreated sewage, and agricultural practices.

A map showing Critical Habitat for guajón
Critical habitat units. Map by USFWS.

Historic news

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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