The exhibition shows the diversity of amphibians and reptiles © NHM Vienna, Chloe Potter

Amphibian or reptile?

What are amphibians?

Amphibians are vertebrates. They may spend the majority of their lives on land, but typically at least at some point during their development – usually as eggs or as larvae – they need water to survive. These two life-phases are reflected in their name: "Amphibia" comes from Ancient Greek and means "both kinds of life".

Adult amphibians also need humid environments to survive as their skin lacks scales, feathers or fur to protect them from drying out. Amphibians, unlike humans, are ectotherms, which means their body temperature changes with the environmental temperature.

Amphibians were the first vertebrates to develop legs and move onto land. They evolved 380 million years ago from bony fish. Today we know 8,500 species of amphibians. New ones are being discovered every year.

All amphibian species living today belong to one of three orders:

Caecilians
Gymnophiona

Ringed caecilian © NHM Vienna, C. Potter

Salamanders
Caudata

Axolotl © NHM Vienna, C. Potter

Frogs
Anura

Colorado river toad © NHM Vienna, C. Potter

What are reptiles?

Reptiles are vertebrates. They mostly live on land and – unlike fish and most amphibians – are able to reproduce without the need for water. They breathe through lungs throughout their entire life cycle; in contrast to amphibians, they do not have larval stages.

They are most closely related to birds. Common to all reptiles is the covering of the skin with horny scales: a protection against dehydration and an adaptation to life on land. Reptiles are ectotherms – unlike humans, their body temperature changes depending on the ambient temperature.

Reptiles evolved 310 million years ago from primitive amphibian-like tetrapods. Today over 12,000 species are known; the greatest diversity is found in the tropics. They exist on all continents except Antarctica.

All reptile species living today belong to one of four orders: