Mammals
The animals like elephant, monkey, deer, bear, horse, goat, cow, human being, etc are called mammals. Mammals give birth to their babies and feed them with their own milk. Bat is a flying mammal. Whale is a mammal that lives in water.
Amphibians
The animals that can live both in water and on land are called amphibians Tortoise, frog, crocodile, etc. are amphibians.
Birds
Birds are the animals that can fly. Their wings help them to fly. They have two legs and two wings. They have feathers and a tail. They have a beak. They generally live in trees.
Sparrow, owl, crow, pigeon, partridge, kiwi, etc. are birds. Most birds can fly. Some birds can swim in water. Some birds like duck can swim in water. They have webbed feet.