Reptiles and amphibians differ from birds and mammals in that they sometimes rely on external heat sources for energy – in most cases from the sun. But this doesn’t make them slow, sluggish or any less efficient – far from it: the UK's amphibians and reptiles are incredibly unique in their character and behaviour, and they have enough energy-saving adaptations to make us humans ashamed of ourselves…

So if amphibians and reptiles are cold blooded, how can they live freely here in the UK where the weather changes considerably between the seasons, from frosty November nights to our summer scorchers? Read on…

The answer is in their cold blooded nature. Sure, being warm blooded has advantages: it allows us big bodies, bigger brains and allows us to be active when the temperatures are low or too high, but it also has disadvantages: namely it costs a lot in terms of energy.

Being cold blooded, the UK's amphibians and reptiles can afford to sit out the weeks or months when conditions aren’t right for moving around to hunt or to breed - a trick warm blooded creatures find much harder to do. One of our native reptiles, the Adder (or Northern Viper) even makes it into the Arctic Circle – the only serpent to do so. Perhaps living in the UK isn’t so bad after all…

Sitting it out..

So from late autumn to early spring, the UK's amphibians and reptiles are around and about, they’re just not visible above ground. All 13 species like to remain dormant in places that offer them protection from frost and predators: rabbit burrows, tree roots, compost heaps, loose soil, and underneath garden sheds are all classic places to see out the winter months in hibernation.

Strangely the Common Frog varies in this habit. Males are often found sitting motionless at the bottom of ponds, possibly to be first there when spring breeding occurs, but also because water temperatures are more stable than land and because ponds are usually free of large predators.

In the winter months grab a torch and visit a garden pond to look for any frogs on the bottom – you might see a pair of eyes looking at you from beneath the silt on the bottom.

Episode 1: Cold Blooded in a Cold Climate
Episode 2: Battlefield Pond
Episode 3: Dragon's Den UK
Episode 4: Snakes in the City
Episode 5: Visitors to UK Shores
Epilogue: Froglife in Cold Blood

BBC Life in Cold Blood
ARG UK
British Herpetological Society
Herpetological Conservation Trust