Once- Extinct Toads Reintroduced to Wild

Summary:
      About 2,000 Kihansi spray toads, once extinct in the wild, have been released and are now living next to  artificial sprinklers in their native habitats. It is the first time an amphibian species that had once been declared extinct in the wild to be reintroduced to the wild. These gold-colored toads with pale white skin that seem translucent so that their abdomen can be seen, are part of a unique group of amphibians that give birth to live young and then carry their newborns on their backs.After being first discovered in Tanzania in 1996, the construction of a hydroelectric dam on the river, that now supplies Tanzania with one fourth of its energy, severely reduced the number of Kihansi spray toads in the wild until five hundred were saved and taken to New York's Bronx Zoo. Still, the numbers continued to decline in the wild until the species was declared extinct in 2009. Then, about fifty of the toads were sent to the Toledo Zoo in Ohio where they were capable of reproducing in captivity. About a hundred of these toads were then sent back to Tanzania where they continued to reproduce until finally being released back into the wild.

Relevance:
     This article is relevant to the term two curriculum because of its connection to the topics of extinction and genetic bottlenecks. These toads could not be found in the wild making them extinct in one sense, but some were taken and kept captive so that they were able to reproduce and be released again. Due to being extinct into being reintroduced, this caused a genetic bottleneck. A bottleneck can reduce a species genetic variation significantly. From thousands in number of the Kihansi spray toads into five hundred, and then reproducing just the remaining toads narrows the amount of genetic variation that had possibly once existed when having the thousands of toads.

http://www.scientificamerican.com/article.cfm?id=once-extinct-toads-reintroduced-to-wild
Author: Douglas Main
Date: December 13, 2012