Adders could soon be hiss-tory in the UK, according to new research.
A nationwide survey by the Amphibian and Reptile Conservation (ARC) Trust found adders have been vanishing from our countryside since 2007.
Adders are the UK's only poisonous snake, but now researchers say they might need conservation.
It's thought lots of adders are killed because they're poisonous, but the ARC Trust says their decline may also be caused by disturbance of their habitat.
Adders aren't the only reptiles in trouble though.
The study found slow worms, common lizards, grass snakes, common toads and common frogs are also becoming less widespread.
The only species among reptiles and amphibians that was found to be increasing its range is the palmate newt.