Snake populations across the world are declining, but researchers don’t know why. (BBC News, The Guardian, New Scientist)

A study published in the journal Biology Letters reviews records of 17 snake populations in 5 countries including France, Nigeria and Australia spanning the period 1997 to 2008. They found that 11 snake populations, including the smooth snake (Coronella austriaca), Britain’s rarest snake, declined sharply and synchronously over a four year period between 1998 and 2002.

Project leader, Chris Reading of the Centre for Ecology and Hydrology, which has its headquarters in Wallingford, UK, says, “This is the first time that data has been analysed in this way, and what we’ve shown is that in different parts of the world we seem to have this steep decline in a short period."

“We don’t have a clue” what might have caused the drop in numbers, he told BBC News.

Snakes are top predators among reptiles, so declines in their numbers could impact how ecosystems function.

Long-term studies have previously shown population declines in fish, amphibians, reptiles, birds and mammals. The causes of these drops are often unclear.

Project leader, Chris Reading of the Centre for Ecology and Hydrology, which has its headquarters in Wallingford, UK, says, “This is the first time that data has been analysed in this way, and what we’ve shown is that in different parts of the world we seem to have this steep decline in a short period.”

“We don’t have a clue” what might have caused the drop in numbers, he told BBC News.

Snakes are top predators among reptiles, so declines in their numbers could impact how ecosystems function.

Long-term studies have previously shown population declines in fish, amphibians, reptiles, birds and mammals. The causes of these drops are often unclear.