September 2006
The mean lifespan of a mammal species is around 2.5 million years, which is relatively brief. Study of a 22 million year rodent fossil record from Spain shows that their patterns of extinction are correlated with long astronomical cycles in the average distance of the Earth from the Sun, and in the angle of the Earth’s rotation. Both these factors might affect climate, which in turn affects species survival.
Full article from Nature here (subscription needed to get past abstract)
Podcast from Nature (free) discussing this finding here.
