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Identifying and Grouping Animals
Animals have different qualities. Based on these qualities, they can be grouped into various classes.
Mammals give birth to their babies, and feed them milk. They are warm blooded. Most mammals live on land, but there are some who live in the sea, like whales and dolphins.
Mammals have hair on at least part of their body. They usually have four limbs with digits ending in claws, nails, or hooves (except whales). They breathe with lungs.
All mammals have a spine or backbone, so they are called vertebrates. Dogs, horses, cats, duckbill platypuses, kangaroos, elephants, dolphins and whales are examples of mammals.
Amphibians are animals that live on land and in water. They lay their eggs in water and babies are born in water. When they are born, they breathe with gills like a fish. However, when they grow up, they develop lungs and live on land. They usually have soft skin.
Amphibians have a backbone or spinal column, so they are called vertebrates. They are all cold-blooded. They lay eggs, usually in a jelly-like mass in water. They have smooth skin without coverings.
Amphibians have four legs without claws or nails on toes. Frogs and salamanders are examples of amphibians.
Birds are animals that have feathers on their body, and are born out of hard-shelled eggs. The feathers on a bird’s wings and on its tail overlap. Since they overlap, the feathers can catch and hold the air. This is what helps the bird to fly, steer itself and land safely on the ground. They are vertebrates. This means that they have a spine.
Birds have a beak and two legs. They also have two wings used for flying. However, ostriches and penguins are flightless. Birds have hollow bones, and are warm-blooded.
Fish are animals that live in water. They have gills, scales and fins on their body. They are vertebrates, that is, they have a back bone. They lay eggs without shells in water.
Fish breathe with gills. They are covered with scales or smooth, leathery skin. They have fins but no legs or toes. They are cold-blooded.
Reptiles are animals that have scaly skin. They are vertebrates. They are coldblooded too. Snakes, crocodiles, lizards, alligators and turtles belong to the reptile class. They lay eggs with leathery shells or give birth to fully-formed young.
Reptiles breathe with lungs and are covered with scales. They have no legs or four legs with clawed toes. Reptiles are vertebrates.
Insects have three body parts: head, thorax and abdomen. They have a single pair of antennae on the head. They also have three pairs of legs originating from the thorax.
Insects often have wings and can fly. Insects are invertebrates, which means that they do not have a back bone or spinal column.