Man’s existence depends on not only the other members of his society, but also on various animals around him. Most big animals that we associate within our daily life are vertebrates. Some common vertebrate animals are cows, dogs, cats, bears, giraffes, rabbits, ducks, alligators, frogs, and turtles. Vertebrates are animals with backbones.
There are five main groups of vertebrates: mammals, birds, fish, reptiles and amphibians. Mammals are animals that have a covering of hair on the skin. They generally give birth to their young, which are breastfed by their mothers.
Fish are vertebrates that live in water, breathe through gills, and have fins. They have an elongated body covered with scales. Birds, on the other hand, are egg-laying, feathered vertebrates. Their forelimbs have been modified to form wings in the process of evolution. Reptiles are vertebrates that lay eggs. Some of them are snakes, lizards, crocodiles, turtles and dinosaurs. They have an external covering of scales or horny plates.
Amphibians, such as frogs or salamanders, are smooth skinned vertebrates, capable of living both on land and in water. They have gills when they are born. However, when they become adults, they develop lungs too.
Vertebrates can be split further, into warm-blooded and cold-blooded animals. A warm-blooded animal, such as a dog or a man, keeps its body temperature the same, except when it is sick. Cold-blooded animals have fluctuating body temperature. It changes according to the surroundings. So if the weather is hot, the animal is warm, and if the weather is wintery, it turns cold!
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