Roads, buildings and farms are preventing Michigan’s only rattlesnake from finding mates outside of their population. A 15-year study shows that fragmentation into smaller, more isolated patches is likely reducing the threatened snake’s chances of survival. Michigan State University conservation biologists traced the family histories of more than 1,000 Eastern Massasauga rattlesnakes caught and released in a U.S. Fish and Wildlife Service-funded project. The new findings, published in the Proceedings of the National Academy of Sciences, surprised even the researchers – the most inbred snakes were 13% less likely to have surviving offspring and had a nearly 12% lower annual survival rate.