Lonesome George

The Pinta Island Tortoise, Geochelone nigra abingdoni, is the rarest animal in the world. This lonely tortoise is the last member of it's species and has aptly, but most depressingly, been given the name of Lonesome George. Discovered in 1971 in the Galápagos, George is now between 60 and 90 years old and is in fairly good shape apart from his lack of friends. Scientists are doing their best to make the preservation of this most critically endangered species possible, but they have yet to succeed in their reproduction efforts. There is currently a $10,000 reward for the discovery of a female Pinta Island Tortoise. 

Reference: http://en.wikipedia.org/wiki/Lonesome_George