Researchers have been monitoring a snake species that has been absent from the UK for approximately 300,000 years.
The UK is home to only three native snake species: the adder, grass snake, and smooth snake. However, a fourth, non-native species—introduced by accident—has begun establishing itself in the region.
Native to central and southern Europe, the Aesculapian snake has been unintentionally reintroduced to the UK, according to BBC Countryfile. Experts estimate that this species last inhabited the UK around 300,000 years ago before disappearing during a past ice age.
This non-venomous snake can grow up to two meters long and primarily feeds on rodents like rats. Adults have smooth scales, round pupils, and are typically grey, olive, or brownish in color. Juveniles feature a distinct dark stripe along the sides of their heads and a V- or U-shaped marking on their necks, according to Frog Life.
Currently, there are three known thriving populations of Aesculapian snakes in the UK, all descended from escaped individuals. One of these populations is located in Colwyn Bay, North Wales.
A recent study by Bournemouth University investigated how these snakes have adapted to the UK's cooler climate. Scientists implanted radio trackers into 21 snakes and monitored their movements over two summers (June–October 2021 and May–September 2022).
The study found that Aesculapian snakes were climbing walls and entering buildings, often hiding in attics. They also sought shelter in garden compost bins, using the warmth to incubate their eggs. Additionally, they adjusted their behavior to cope with the colder temperatures by digesting food and preparing to shed their skin as ways to retain heat.
According to BBC Countryfile, the research showed that these snakes coexisted with suburban wildlife without significantly impacting native species.
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