UK's adder, despite being venomous, has caused only 55 deaths since 1722, report shows.

The UK's only venomous snake, the adder, has caused 55 deaths since 1722, according to a report. Easily identified by a zig-zag pattern and red eyes, adders are shy and typically only bite if stepped on. Bites can cause swelling, bruising, and, in severe cases, vomiting, but are not usually life-threatening. Adders grow up to 80cm and are most often seen basking in the sun during early spring after hibernation.