David Fleay
In the early 1930s, Fleay went to Tasmania to try to capture Thylacines (also called Tasmanian tigers). He was not able to find any Thylacines in the wild.  So he decided to run a breeding program with Thylacines in zoos.  He wanted to breed more Thylacines to save them from becoming extinct. But the Tasmanian government did not allow Fleay to run this program. We now know that the last definite sight of a Thylacine in the wild was in 1930. By 1936, the last Thylacine living in a zoo died, and this species was extinct.