Animals of the World

Life on Earth is divided among many kinds of animals, each adapted to particular environments and ways of living. Mammals form a familiar group that includes hooved grazers such as deer, predatory carnivores, primates, and marine species. Deer and other hooved animals are typically plant-eaters with digestive systems suited to processing grasses and leaves, and many live in herds that offer protection from predators.

Reptiles make up another major group, including snakes, lizards, turtles, and crocodiles. They are cold-blooded, meaning their body temperature depends on the surrounding environment, so many are most active in warm climates. Snakes such as boas and pythons subdue prey by constriction, while other reptiles rely on camouflage, speed, or powerful jaws. Amphibians, fish, and the vast array of invertebrates including insects and arachnids round out the diversity of the animal world.

Each group shows adaptations that fit its environment, from the streamlined shape of a fish to the protective shell of a turtle. Animals interact within ecosystems as predators, prey, and competitors, and changes to their habitats can threaten their survival. Many species are now the focus of conservation efforts, with zoos and reserves working to protect endangered animals and breed them in safety.

Frequently asked questions

What do deer and other hooved animals eat?

They are mainly plant-eaters, feeding on grasses, leaves, and shoots, with digestive systems adapted to break down tough plant material.

Why are reptiles more active in warm weather?

Reptiles are cold-blooded, so they rely on external heat to warm their bodies. They tend to be most active when their surroundings are warm.

What threatens many animal species today?

Loss and change of habitat are major threats, which is why many animals are now protected through conservation programs and breeding in reserves and zoos.