Amphibians and reptiles

Six species of amphibian occur naturally in Scotland, and three common species of reptile are found naturally on land.

Scotland’s native amphibians:

• common frog
• common toad
• natterjack toad
• great crested newt
• palmate newt
• smooth newt

Our native reptiles:

• adder
• common lizard
• slow worm (a type of lizard)

Coll has a colony of sand lizards, introduced to the island some time ago. Several species of marine turtle – also reptiles – have been recorded around our coast.

Amphibians and reptiles may be referred to collectively as herptiles. All herptiles hibernate during the winter.

How amphibians and reptiles differ

Amphibians and reptiles first evolved long before warm-blooded animals. They can’t control their body temperature internally.

Scotland’s cool climate presents an obvious challenge to herptiles. Reptiles soak up the sun’s heat in sheltered places until they’re warm enough to hunt prey at speed. Amphibians cope in a cooler environment by living at a more leisurely pace.

Amphibians and reptiles also differ in other ways.

Amphibians

Amphibians are equally at home in the water and on land. Frogs, toads and newts have soft, water-permeable skin. This lets them breathe underwater as well as on land. But it means that they must spend their time out of the water in damp places like wet grassland or beneath fallen logs or leaf litter.

Amphibians need water to breed in. Eggs are laid as spawn in the early spring and swimming tadpoles soon emerge. Once their legs have grown and their tails have shrunk, they will leave the pond as tiny adults.

Newts have a similar life cycle but lay eggs which are individually stuck to plants. The young are like mini-newts but have frilly gills to absorb oxygen from the water during this phase.

Reptiles

Reptiles have dry, scaly skin, which prevents them from drying out. They don’t need to return to the water to breed.

Breeding is a challenge for reptiles in our cool climate. Most reptiles breed by laying eggs on the ground, but this isn’t a good strategy in Scotland. Instead, all Scottish reptiles retain their eggs inside their bodies and give birth to live young.