Species Focus - Adder (Vipera berus)

Mid- and late summer are good times to look out for Britain’s only venomous snake, the Adder. At this time of year, gravid females can often be seen basking prior to giving birth towards the end of summer. They can be distinguished from the harmless Grass Snake by the zigzag band running along the middle of the back. Occasional melanistic (all-black or nearly so) specimens have been found in Snowdonia.

Despite their venomous nature, Adders are shy and inoffensive animals that will only bite as a last resort, usually when picked up or inadvertently stepped on. They are also very susceptible to disturbance, so if you are lucky enough to spot one, please admire it from a distance and try to avoid disturbing it.

Adders are widespread in North Wales, and can be found in heathlands, moorlands, fens, coastal dunes and cliffs, and along woodland edges. Sadly, their populations have been declining steeply in recent years. They are currently only protected against deliberate killing and injury, and against trade; however, fuller protection for the species is being considered. This makes it especially important to better understand its range, so please submit your records, ideally with photos, to the Cofnod ORS or the LERC Wales App.