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AN UNFAMILIAR SNAKE IN BRITAIN
31/10/2024
Although familiar to us in continental Europe, the UK is not in the native range of the Aesculapian snake Zamenis longissimus (Laurenti, 1768); at least it hasn’t been for many tens of thousands of years according to the fossil record. There have been escapes from zoos, though, and these have now founded breeding populations, notably in Wales and London. The species is recorded at up to 2000m in the Alps so, although the UK is thought to be too cold for them, I am not all that surprised that, once out in the wild, they are settling in here.
Aesculapian snakes are big as their scientific name suggests – up to 2m long – and they are constrictors, suffocating their larger prey by squeezing like a boa would. They eat rats and various small mammals as well as, unfortunately, birds and nestlings: they are excellent climbers, aided by the ventral scales they have which are sharply angled.
Recent research by Tomas Major of Bournemouth University et alii (see Bangor University paper[1]) has revealed that this snake species is using anthropogenic habitats where they can be warm, which of course they must as they are cold-blooded (poikilothermic). Such places have been found to include inhabited buildings where there are cavities in walls and attics, as well as sites such as compost heaps.
Aesculapian snake seen in Switzerland
Attribution: Felix Reimann, Wikimedia Commons
Creative Commons Attribution-Share Alike 3.0 Unported licence. Thank you.
Betts Ecology is always interested to hear about new species in the UK, even if some are invasive. Given the density of human development in the UK, I see no reason why these snakes will not continue to spread – do keep a lookout for them and let us know, with a photo) if you see one, but remember that juveniles look very like our native barred grass snake Natrix helvetica (Lacépède, 1789). Aesculapian snakes are not venomous, but please don’t disturb them, rather inform your local Wildlife Trust. Remember that they are a Wildlife and Countryside Act schedule 9 species[2].
