Animals are one of the basic groups of life on Earth. Animals are divided into six basic groups. Those are Invertebrates, Amphibians, Birds, Fishes, Mammals, and Reptiles. Except for invertebrates the other five also named as Vertebrates.
Classifications of Animals
All animals are divided into three categories on the basis of their eating habits.
Ex: Cow, Elephant, Goat, etc;
Animals which feed directly on plants are called Herbivorous. This includes leaves, grass, flowers, fruits, roots.
Ex: Lion, Tiger, Eagle, etc
Animals that eat the flesh of other animals are called Carnivorous. This includes meat, fish
Animals which eat both plants and flesh of other animals are called Omnivorous.
Variety in Animals
Animals live in different types of surroundings. This world is full of thousands of animals. Some are Microscopic animals like amoeba and large animals like Mammals.
Animals are found in on land, in water, and in air. The entire animal kingdom is divided into smaller groups according to their body features.
Animals that live mostly on trees are called arboreal animals.
Ex: monkeys, lizards, tree frogs, geckos, some insects
Most of the arboreal animals have elongated limbs to swing efficiently from branch to branch. Very important thing is that animals living in trees can grip well. Some animals (like squirrels) have ankle joints that are highly flexible. It helps them to move here and there through trees. Some others have adhesive pads (like geckos/frogs) to grasp branches.
Animals that live on land on the surface of the ground or in burrow below the surface of the ground are called terrestrial animals.
Ex: tigers, rabbits, earthworms, elephants, buffalos, some insects
Animals that live in water are called aquatic animals. All aquatic animals are not found in the same type of water. Some kinds of fish are found in lakes and streams. Some are found in saltwater.
Ex: frogs, fish, tortoise, whales
Especially fish do not have hands or legs. Their body is made like a boat to make the swim in the water easy. They do not have lungs like us, they breathe through gills.
Animals that spend the greater part of their lives in the air are called aerial animals. Ex: bats, birds, some insects
Animals that live both on land and water are called amphibious animals. Some other animals like water-snakes, crocodiles, tortoises, crabs also spend a part of their life in water and apart on land. Ex: toads, salamanders.