The Wildlife Conservation Society’s Bronx Zoo, the Toledo Zoo, Tanzanian government, World Bank and other partners have reintroduced 2,000 Kihansi spray toads into the Kihansi Gorge in Tanzania. This is the first example of an amphibian species that had been declared extinct in the wild being reintroduced into its native habitat.

The repatriation effort marks a major milestone for a species declared extinct in the wild in 2009. It is the result of a 12-year partnership to breed the toads in captivity while its habitat was restored.

Representatives from each of the partnering organizations joined WCS for the release in the Kihansi Gorge at the end of October: the Toledo Zoo, World Bank, University of Dar Es Salaam, International Union for Conservation of Nature (IUCN), Tanzania Wildlife Research Institute, Sokoine University of Agriculture, Tanzania Electric Supply Company, and local Tanzanian villagers all took part.

The Kihansi spray toad was first discovered in 1996, living in a five-acre micro-habitat created by the spray of nearby waterfalls in the Kihansi Gorge. In 1999, the construction of a hydroelectric dam 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. The dam, generating nearly one-fourth of Tanzania’s electrical supply, reduced the flow of the Kihansi falls by 90 percent, drastically lessening the mist zone.

The toad was last seen in the wild in 2005, and in 2009, it was declared extinct in the wild by the IUCN. Although the ultimate cause for extinction is still debated, it is likely a combination of habitat change and the emergence of chytrid fungus, a virulent pathogen which is responsible for alarming population crashes and extinctions of amphibian species across the world.

As the spray toad population rapidly declined, an agreement between WCS and the Tanzanian government was reached. Bronx Zoo scientists and Tanzanian officials collected an assurance colony of 499 Kihansi spray toads from the gorge. The small colony was brought back to the U.S. to initiate the off-site conservation program. Special microhabitats meeting all the environmental parameters necessary for the toads to survive were replicated in bio-secure facilities at the Bronx Zoo and later the Toledo Zoo. Both zoos were successful in breeding the toads and increasing their numbers so reintroduction efforts could commence.

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