The Potter Park Zoo team shipped 1,800 Puerto Rican crested toad tadpoles to Puerto Rico last week. These tadpoles were released in the wild as part of the Puerto Rican Crested Toad Conservancy (PRCTC) efforts to restore the population of this endangered species. The PRCTC is a team effort comprised of zoos, individuals, and organizations working together for the long-term survival of the Puerto Rican crested toad in the wild.
The Puerto Rican crested toad (Peltophryne lemur) was thought to be extinct until 1967 when a small population was discovered on the northern part of Puerto Rico. It is the only toad native to Puerto Rico and is listed as Critically Endangered on the IUCN Red List due to habitat loss and competition from the invasive marine toad.
In 1984 the Puerto Rican crested toad became the first amphibian to receive Species Survival Plan (SSP) status within the Association of Zoos and Aquariums. In addition to the captive breeding program, the SSP recovery goals include the protection and restoration of existing habitat, island-wide educational programs, and the creation of new breeding ponds. The Potter Park Zoo team has sent tens of thousands of tadpoles to Puerto Rico as a member of the SSP breeding program.
Puerto Rican crested toads require a very specific environment for breeding when in human care requiring the conditions of the spring and fall rainy seasons in Puerto Rico to be replicated. To achieve this the zoo team cools the toads to 66 degrees for one month to promote gamete development. During this time, they are in torpor (a state of inactivity) and do not eat. When the month has passed, the toads are warmed to 82 degrees and begin feeding again. To prevent the spread of disease they are given daily anti-fungal baths for a week prior to the breeding event.
Toad pairings are recommended by the SSP coordinator and Potter Park Zoo was asked to breed two pairs of toads this year. While some toads will breed without any assistance, most require hormones to encourage egg laying and fertilization. The tanks used for breeding are equipped with rain bars and Puerto Rican crested toad calls are played around the clock. Once eggs are laid, the adult toads are removed from the tanks and returned to their holding tanks.
Eggs develop quickly and tadpoles hatch after only 24 hours. While adult toads are carnivorous, tadpoles eat algae and other plant material. They remain at Potter Park Zoo for approximately a week, giving them time to grow a bit more before they are shipped to Puerto Rico for release.
Puerto Rican crested toad tadpoles morph into young toads approximately 2-3 weeks after hatching. Since these toads breed in temporary ponds in the wild, their tadpoles need to morph into toads quickly before the pond dries up. However, it may take many years for them to grow to their adult size of 2-3”.
Guests can visit the Puerto Rican crested toads in the Reptile building at the zoo.