In our world of living things we have plants, animals and people. Plants belong to a group called the Plant Kingdom while animals and people belong to the animal Kingdom. Look around you and you will see many different types of animals. Some animals are tiny while others are very large. Some animals are soft and long, while others are hard and rounded. Different types of animals which are alike in certain ways are put into groups. Let us find out how animals are put into groups. We can put animals into groups by studying their behaviour. We want to know how their bodies work, how they live, how they produce their young, how they find their food, what they eat, how long they live, and so on. We also have to examine the different parts of their bodies. When we examine them, here are a few questions we must ask ourselves, do they have scales, feathers or fur on their bodies? How many legs do they have? How many wings are there? Are there fins? But the first and most important question is, do the animals have backbones or not? All animals with backbones are put into one big group called vertebrates. All animals without backbones go into another group called invertebrates.