Amphibians were the only vertebrates on land in the late Devonian and early Carboniferous. Radiation of forms occurred during the early Carboniferous period. Some forms reached 4 m in length and some resembled reptiles. Amphibians began to decline during the late Carboniferous. Some are aquatic and some are terrestrial.
Aquatic forms swim sinusoidally or walk along the bottom of streams or ponds.
They capture prey by flicking the sticky tongue which is attached anteriorly. Predator avoidance aided by camouflage color patterns and distasteful or poisonous mucus secreted by skin glands. Bright coloration is common in poisonous species. They are legless and almost blind.