The moufflon is a wild sheep from Corsica, Sardina and Cyprus. In 1957, a male and a female from Corsica were taken to another island, this one in the southern Indian Ocean, in an attempt to establish a herd for sport hunting. The pair thrived on Haute Island, and the resulting population peaked at about 700 head in the 1970’s, thereafter oscillating between 200 and 600. Ok, so far so weird, but so what? Well it turns out that genetic diversity hasn’t behaved as expected. By rights in such a small, isolated, inbred population it should have decreased markedly as a result of genetic drift. But according to this, it hasn’t. The reason is probably strong natural selection, according to the authors of the study, who compared DNA from the original founding couple to that of the present herd.