In order to better study the animals, scientists have categorized them according to their characteristics. The general classification / categorization of animals is based on whether they have a spine or not. They are therefore divided into vertebrates (animals with backbones) and invertebrates (animals without backbones).
| Category | Subcategory | Description |
| VERTEBRATES | Amphibians | They are born and grow up initially in the water. They then develop the ability to live on land. They lay eggs in the water (e.g. frog) |
| Reptiles | They have dry skin and live either in water or on land. Some have legs, which are relatively small. (e.g. snake) | |
| Fish | They live and reproduce in the water. They have scales, fins and gills. (e.g. bream) | |
| Birds | They have wings and lay eggs with hard shell. Some of them can fly and some others cannot (e.g. chicken) | |
| Mammals | Animals that breastfeed newborns. They live in the air (fly), in the water or on land. (e.g. human) | |
| INVERTEBRATES | Annelids | Animals with long and soft skin living in the ground or in the water. (e.g. worms) |
| Arthropods | They have legs and their body is covered with hard shell. (e.g. insects, spiders) | |
| Crustaceans | Animals with soft body living on land or in water (e.g. squid). Some of them have a hard shell. (e.g. lobster) | |
| Sponges | Their body has many tiny pores. They live mainly attached to rocks in the water. | |
| Echinoderms | Their body is covered with plaques or hard needles. (e.g. Sea urchin) | |
| Cnidarians | They live in the sea and produce poison with which they kill their prey, which are usually small marine animals. (e.g. jellyfish) |