Adder Genetics

Female european adder
Snake experts from ZSL's Institute of Zoology, Natural Earth and Oxford University have teamed up to perform a vital health check on Britain’s only venomous snake, the adder, following worrying declines.

The adder was once a common sight in large parts of the British countryside but in the last decade it has slipped into decline. Surveys suggest a third of remaining adder populations may comprise fewer than ten adults.

We believe this is down to the disappearance, degradation and fragmentation of habitat, resulting in smaller and more isolated populations of this enigmatic reptile. It is feared that these populations, particularly in the English Midlands, are not able to maintain a healthy level of genetic diversity, their resilience to disease will be reduced and a concentration of genetic defects could occur, leading to local extinctions.

For the first time, our team of snake experts are heading into the undergrowth to obtain genetic samples from adders. This simple, harmless test involves taking a DNA swab, which can be used to determine current levels of genetic diversity.

Dr Trent Garner, Senior Research Fellow at ZSL’s Institute of Zoology said: “Genetic diversity has been shown to be a key component for successful adder populations in Sweden and Hungary, but has yet to be studied in the UK. Our goal is to provide the first insights into how population size and isolation may be related to genetic diversity of the UK’s adders.”

Fewer snakes in the grass

Watch our video to find out more about Britain's adder genetic diversity from our experts out in the field