Oakland Zoo, in partnership with the AZA, is breeding Puerto Rican Crested Toads (Peltophryne lemur) whose offspring will be released into the wild in Puerto Rico.The Puerto Rican Crested Toad (PRCT) was once common throughout Puerto Rico and Virgin Gorda. Unfortunately, habitat loss and the introduction of non-native animals have led to a major decline. The toads are listed as threatened by the United States Fish and Wildlife Service (USFWS) and Critically Endangered by the International Conservation of Nature and Natural Resources (IUCN). In fact, the PRCT was thought to be extinct from 1931 until its rediscovery of a small population in 1966. Currently, there is a small population in Guanica National Forest in Puerto Rico. The toads have not been observed on Virgin Gorda in over 30 years. In 1984, in an effort to save them from extinction, PRCT were the first amphibians to receive Species Survival Plan (SSP) status through the Association of Zoos and Aquariums (AZA). In coordination with USFWS, and the University of Puerto Rico, captive PRCT are bred each year and tadpoles are sent to Puerto Rico for release into closely monitored ponds in Guanica National Forest.
Habitat loss is the most pressing issue for Puerto Rican Crested Toads. They breed in small seasonal pools called Leks. Breeding must coincide with heavy rains and in a dry year breeding may not occur at all. When these seasonal ponds are drained for agricultural or urban development, it reduces the number of breeding opportunities for the toads. In fact, it was the draining of a seasonal pond in the Guanica National Forest in 1984 that led to the discovery of a small population of PRCT. The practice has since been stopped.
The Indian Mongoose (Herpestes auropuntatus) was introduced to the Caribbean islands in the late 1800s in an effort to reduce the rat populations in the sugar cane plantations. However, they are voracious and opportunistic predators and prey on all types of vertebrate animals including birds, reptiles and amphibians. The mongoose has been blamed for losses to the poultry industry as well as small game animals. They have been blamed for at least 7 native reptile and amphibian extinctions in the West Indies. Mongoose are prolific breeders and are also considered reservoirs for several zoonotic diseases including leptospirosis and rabies.
Non-native invasive species
In 1920, the Cane toad (Bufo marinus), native to Central and South America, was introduced to Puerto Rico in an effort to combat a beetle infestation in the sugar cane plantations. The cane toad was very successful at eliminating the beetle problem, in fact they were so successful, that in in 1930’s scientists began recommending them to control other agricultural pests and the cane toad is now an invasive species throughout the Caribbean and Australia. Cane toads are efficient breeders, able to breed year round rather than seasonally like many amphibians do. Tadpoles are toxic to most predators so tend to survive in large numbers. Adult toads secrete a toxin from the parotid gland behind their eyes. They are also opportunistic feeders, eating variety of invertebrates as well as small vertebrate species and even carrion, allowing them to adapt to almost any environment. This makes them well suited to displace native species that compete for food, shelter and breeding sites.
Learn as much as we can about the PRCT in the wild and in captivity.Release tadpoles back to the wild: Identify additional sites for tadpole release. Monitor these sites long term to determine their viability in the future.
Outreach and education
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. Unfortunately, most Puerto Ricans have never heard of the crested toad, nor are they aware of its plight. Historically, the original common name for crested toads was “sapo concho,” but the name soon became synonymous for the more commonly seen cane toad making conservation efforts difficult. As a result, the recovery group decided to change the common name for crested toads to “sapo concho Puertorriqueno” and the name for cane toads to “sapo comun” to help differentiate between the two species.
Current field research involves mapping of current and historical ranges with the hopes that new territories may be established. In captivity, nutritional research is critical. Toads are prone to hypovitaminosis A which can affect not only the adult toads, but inhibits tadpole development as well.
On site help for the PRCT
Oakland Zoo is breeding PRCTs onsite in our Biodiversity center. The offspring of these toads are sent to Puerto Rico where they are released into man-made, closely-monitored ponds in the Guanica National Forest.
Outreach and education
Zookeepers and educators attend local festivals and meet with local conservation groups to get the word about the plight of the Puerto Rican Crested Toad.
Quarters for Conservation
Oakland Zoo selected the Puerto Rican Crested Toad program as a 2016-2017 featured project, which raised funds to benefit our on-site conservation efforts on behalf of this species.