A fourth species of snake is breeding in the wild, despite Britain being too cold for it to survive.
The two-metre-long Aesculapian snake has been tracked by Tom Major and his colleagues at Bournemouth University to understand how they’re surviving in their new habitat.
They appear to be exploiting the warmth of buildings and compost heaps, becoming an invasive species in parts of the UK.
The snakes went locally extinct in the last Ice Age and has not been seen in the UK for 300,000 years. Now they are found in Colwyn Bay in north Wales, Bridgend in south Wales, and Regent’s Park in London.
Species are known to be pushed out of areas by climate change and habitat change, into places that don’t necessarily fit their needs.
Researchers found male snakes have a “distinct preference” for buildings while female snakes prefer woodland areas. They also found snake eggs in a compost heap at a house.
“For snakes, anthropogenic structures such as buildings and culverts provide shelter, thermoregulatory opportunities and egg-laying sites,” scientists say.
“We observed Aesculapian snakes actively seeking and returning to use inhabited buildings and were observed climbing large structures to access the lofts and wall cavities of houses.”
Researchers suspect the snakes may be using hedgerows and culverts to safely spread into new areas, avoiding roads.
The yet-to-be peer-reviewed study said these are “unusual behaviours” compared with snakes native to the UK that often avoid sprawling urban areas.
The Adder and the smooth snake, for example, are “rarely found” in environments dominated by humans. Even grass snakes that can sometimes be found in artificial environments like garden ponds use such features less extensively.