Extinct in the Wild, Kihansi Spray toad breeding and on display at Bronx Zoo

Highly unusual toad lived in just 1 small gorge in Tanzania
February 2010 - The Wildlife Conservation Society's Bronx Zoo have announced the opening of a new exhibit featuring the Kihansi spray toad, a species listed as extinct in the wild last year by the International Union for Conservation of Nature (IUCN).

Females give birth to live, fully formed young - Not tadpoles
The small, yellowish toad once occurred in large numbers but was only found in a verdant, moist five-acre microhabitat in the Kihansi gorge of Tanzania. This species is unusual among toads; females give birth to live, fully-formed young, rather than laying eggs that hatch into free-living tadpoles.

Highly specialised habitat
The exhibit is as unique as its inhabitants. Keeping the toads comfortable necessitated the construction of a specialized system that filters, cools, and treats the water with ozone. The treated water is then delivered to the animals through a series of nozzles that create a fine mist within the enclosure.

Reintroduction plans
For nine years, a team of herpetologists at the WCS's Bronx Zoo has been working behind the scenes on a conservation program intended to save the Kihansi spray toad from disappearing altogether by propagating the species for eventual reintroduction into its natural habitat.

Hydro electric dam wiped out wild population
In 2000, the construction of a hydroelectric dam in the Kihansi Gorge of Tanzania was predicted to dramatically change the Kihansi spray toad's habitat. The micro-habitat where the toad lived was dependent on the mist created by the waterfalls in the gorge. Although this dam is vital to the Tanzanian economy in that it generates one-third of Tanzania's total electrical supply, its construction reduced the original size of the Kihansi falls to 10 percent of its former flow, drastically lessening the mist zone in which the toads thrived.

Following an agreement between WCS and the government of Tanzania, WCS scientists and Tanzanian officials collected an assurance colony of 499 Kihansi spray toads from the gorge. The small colony was brought back to New York to initiate the off-site conservation program.

2 captive populations
Scientists are still debating the ultimate cause of extinction of this species in the wild, but it was probably a combination of habitat change and the emergence of infective chytrid fungus, which is responsible for alarming crashes and extinctions of amphibian species in many parts of the world. The only remaining population of Kihansi spray toads consists of more than 4,000 individuals residing at WCS's Bronx Zoo and the Toledo Zoo.

Sprinklers to recreate environment
After being propagated at WCS's Bronx Zoo for nine years, the project is entering the repatriation stage where WCS is working with the government of Tanzania and several international partners to return a small population to a facility at the University of Dar es Salaam within the next year. The Tanzanian government has also been managing the Lower Kihansi Environment Management Project in the gorge. A system of sprinklers, replicating the toad's habitat, has been installed in preparation for the species' return. The ultimate goal of WCS and partners is to return the toads to the Kihansi gorge when habitat conditions can be assured for their long-term survival.

"The Wildlife Conservation Society is taking a leading role to ensure this toad does not disappear from the planet by playing an active role in its conservation," said Jim Breheny, WCS Senior Vice President of Living Institutions and Director of the Bronx Zoo.