Lesson 8: More on Animals.

Animals can be as small as an ant to as large as an elephant. Some of the smallest animals are found in the soil and in the seas. There are animals that are so small that you need a microscope to see them. Some are a bit larger, but just a bit. Of all animals, the insects are the most numerous. Insects are present almost everywhere on earth, from forests to glaciers and from sea-shores to sea floors.

Most large animals have a backbone. All of the largest animals, both on land and in the sea, have backbones. The largest animal on land is the African elephant. In the sea, it is the blue whale. In fact, the blue whales are the largest animals to live in the earth. Even though the whales live in the oceans, they belong to a group of animals called mammals. Mammals are unique amongst many animals in that they give birth to young ones and feed them after their birth. Almost all other animals lay eggs. The eggs nourish the young ones until they hatch.

Of the animals that lay eggs, the largest ones are once again seen in the oceans. Fishes are a large group of animals that live in both fresh water (river / lakes) and salt-water (seas and oceans) bodies. There are many fishes that grow over five feet long.. However, the largest fishes belong to the group of sharks. Sharks are a special group of animals that are called “cartiligenous fish”. They do not have a true backbone, but have a spinal cord. The largest amongst sharks is the great white shark (20 feet). The smallest sharks are not very common and they grow to less than a feet in size.

Besides mammals, whales, sharks and other fishes, there are also many large animals that do not have a backbone. Some of the largest such animals belong to the family of squids. The giant squid is known to know up to 13 meters long from end to end, much larger than a great while shark. However, this animals lives deep inside the oceans and is rarely seen above. Apart from the giant squids, octopuses are also known to reach large sizes (~12 feet across).

Even though the animals mentioned above are the largest, they are not the most numerous. The most numerous animals on earth are, as noted before, the insects. Insects come in very many sizes and shapes and places too. Even though they are present almost all over the world, insects like warm and humid places: like the equatorial rain forests.

Even though we have studied the plants and animals separately, one cannot live without the other. They are what we call “interdependent”. While plants give food to animals, animals help the plants to reproduce by pollinating them and by dispersing their seeds.