Bio Facts: Toad, Puerto Rican Crested
Puerto Rican Crested Toad
Puerto Rico and British Virgin Islands
Semi-arid, rocky areas of seasonal evergreen forest; it has been recorded from sea level up to 50 m above sea level.
Adult length: 2.5 - 4.5 in (6.35 – 11.43 cm); coloration and appearance: color ranges from brown to yellow brown with black or brown patches with the ventral surface a creamy white with some dark mottling, pebbly-skinned; male and female frogs have prominent crests above their eyes and snouts that are turned up; female’s skin is much rougher and crest a bit higher than their male counterpart’s, and they are also generally larger than the males; sexual dichromatism (males are yellower than females) is most obvious when males are in breeding condition. Males also possess prominent nuptial pads on the first and second digits of the front feet.
Unknown in the wild; up to 10 years in captivity
In the wild, they eat worms, insect larvae, insects, and other invertebrates; in the Zoo, they are fed crickets, worms and other invertebrates.
IUCN – Critically Endangered; USFWS – Threatened
Puerto Rican crested toads are nocturnal, escaping the sun’s intense heat during the day by entering holes and fissures within the Karst. The toads are seldom observed throughout the year except during breeding events.
Reproduction is sporadic, occurs only at certain times throughout the year, and is highly dependent upon rainfall. The rain provides temporary pools, which the frogs utilize to breed. After it rains, males gather at the temporary pond and call females. It is suspected that light rains (less than 7 inches) attract toads within 1-2 kilometers (1 mile) of the pond and heavier rains (7-13 inches) are sufficient to attract the entire breeding population from up to 3 kilometers (2 miles) away.
Females lay long, black strands of eggs—sometimes up to 15,000. Shortly after, the females leave the pond and the males remain for 1 to 2 days before dispersing. Eggs hatch after 24 hours and the tadpoles metamorphose within 18-25 days. It has been reported that some toadlets were found as far as 4 linear kilometers (2.5 miles) from the breeding pond. The toadlets clump together to save body moisture as they move away from breeding ponds.
The Puerto Rican crested toad was first described in 1868 by Cope. The crested toad was thought extinct from 1931 until its rediscovery in 1966.
In Puerto Rico, toad populations were once divided into two distinct populations; one in the north and one in the south. Mitochondrial DNA analyses suggest that these two populations have been separated for up to 1 million years and are genetically distinct. Unfortunately, northern toads have not been seen in the wild since 1988 and biologists consider the population extirpated. Currently, the only known wild population is the southern form, which resides in a small pond located within Guanica National Forest.
In an effort to save this species from extinction, a Species Survival Plan (SSP) was created through the American Zoo and Aquarium Association (AZA). The SSP goals include island-wide education and outreach, research, the protection of existing habitat, the creation of new ponds, and the establishment of at least five self-sustaining populations in the wild. A reintroduction program is a large component of the recovery plan for this species. Each year, captive toads from zoos and aquariums in the United States and Canada are bred, and tadpoles are sent to Puerto Rico for release.
SSP members have worked closely with partners in Puerto Rico (USFWS, Puerto Rican Department of Natural and Ecological Resources (DNER), University of Puerto Rico, Company of National Parks at Juan Rivero Zoo, Inciativa Herpetologica, Inc. and Ciudadonos del Karso) for more than twenty years towards the recovery of this unique species.
The species is considered to be extinct at Virgin Gorda Island. It apparently occurred in St. John (U.S. Virgin Islands), but it is currently believed to be extirpated there.
Listed as Critically Endangered because of a population decline in the past ten years estimated to be over 80% as recorded from direct observation; and because its Extent of Occurrence is less than 100km2 and its Area of Occupancy is less than 10km2 and there is continuing decline in the number of mature individuals; and because its population size is estimated to be less than 250 mature individuals, there is a continuing decline in the number of mature individuals, and all individuals are in a single subpopulation.
The main factor leading to the decrease of Peltophryne lemur populations may be the destruction of their breeding grounds. Preservation of these sites may be the only way to prevent the extinction of the Peltophryne lemur species. Captive breeding programs such as the Species Survival Plan (SSP) are also being implemented. The main goal of this program is to captively breed endangered species in North America, as well as some foreign species. The SSP has been working to preserve the Peltophryne lemur for about 15 years and it was the first amphibian considered for the program (Johnson 1999).
Another contributor to the decline of Peltophryne lemur is the introduction of the giant marine toad (Bufo marinus) in the 1920s. The purpose of this toad was to control sugar cane grubs. However, the Puerto Rican Crested Toad has had to compete with the giant marine toad for breeding sites, food, and general habitat (Herpitarium 2001). Rats and the Indian mongoose are also believed to compete with Peltophryne lemur.
The last remaining population at Guánica is highly vulnerable to environmental catastrophe. Hurricanes, tidal waves, floods, prolonged drought or increased salinity levels could wipe out the entire population or reduce it to unsustainable numbers.
The SSP developed a breeding site in both Southern and Northern Puerto Rico. The Northern-breeding site was not protected and no toads have been seen there since 1988. The Southern site has been protected, however, at most, 1,000 adult toads have been observed there. Over the 15 years that SSP has been working with this amphibian, the population of Peltophryne lemur at the Southern site has decreased to around 200 adults (Johnson 1999).
Recovery goals for this species also include island-wide education outreach, protection and restoration of existing habitat, creation of new ponds to support six self-sustaining populations (three in the north and three in the south) and research. Recovery efforts are primarily directed through the USFWS, Department of Natural and Ecological Resources (DNER) and the AZA. Additional recovery group partners consist of: University of Puerto Rico, Compañia de Parques Nationales at Juan Rivero Zoo, Ciudadanos del Karso and Inciativa Herptologica, Inc.
One of the primary goals identified for the education outreach component of the recovery program is to foster island-wide awareness for this rare endemic species. Puerto Ricans are very fond of their beloved coquí (Eleutherodactylus sp.), and sounds and images of the frog can be heard and found everywhere. Unfortunately, most Puerto Ricans have never heard of the crested toad, nor are they aware of its plight. Historically, the original common name for P. lemur was “sapo concho,” but the name soon became synonymous for the more commonly seen B. marinus, making conservation efforts difficult. As a result, the recovery group decided to change the common name for P. lemur to “sapo concho Puertorriqueño” and the name for B. marinus to “sapo común” to help differentiate between the two species.
The release of tadpoles, rather than toadlets, is believed to increase the likelihood of imprinting on the natal pond habitat and allows natural selection to occur at a stage in which large losses can be buffered by the relatively high numbers of released animals. To date, over 167,000 tadpoles and 1,000 toadlets have been released back to the wild. The SSP now releases tadpoles at three sites in Puerto Rico, establishing new reintroduced populations, furthering recovery efforts for the crested toad. The AZA Conservation Endowment Fund has provided over $60,000 in support of Puerto Rican crested toad conservation projects.
Jacksonville Zoo History:
This highly endangered species first arrived in our animal collection in 2008 when we received members of their ‘southern’ population. Specimens of the much rarer ‘northern’ population arrived in 2010. The Jacksonville Zoo and Gardens has successfully bred the northern population of this species and shipped specimens for release in Puerto Rico.