In 2006 biologists studying the only timber rattlesnakes in the state of New Hampshire recorded something alarming: a population crash. The already rare animals – numbering about 40 in total – began dying in unusually large numbers. No more than 20 rattlesnakes survived, and the population remained at that new super-low level five years later. Many of the snakes showed signs of a severe skin infection on their heads and bodies just before they died.

It was an early sign of a deadly fungal disease that is now sweeping through the snakes of eastern North America. Today at least 30 species are affected. “Snake fungal disease” has been documented in more than 16 US states and in parts of Canada. How worried should we be? Snake fungal disease generally begins with a relatively mild skin infection, often – but not always – where a snake’s skin has been physically damaged. READ MORE