Animals of the World

Animals are sorted into groups based on shared traits, which helps describe the variety of life. Birds, warm-blooded and feathered, include scavengers such as vultures, large soaring birds that feed mainly on dead animals and help clean the landscape of carcasses. Their broad wings let them glide for long periods on rising air while searching the ground below for food.

Reptiles form another distinct group, cold-blooded animals with scaly skin. Among the snakes, vipers are venomous hunters with long fangs that fold back when not in use, injecting venom to subdue prey. Other reptiles, including lizards, turtles, and crocodiles, show how the group has adapted to environments ranging from deserts to rivers and the open sea.

Hooved mammals and other grazers add to the picture. Wild relatives of domestic sheep, such as the urial, and the slender vicuna of the South American highlands, are well suited to rugged or high-altitude country. Together with carnivores, primates, amphibians, fish, and invertebrates, these animals form the wider web of life, in which each species occupies a role and many now depend on conservation to survive. Organizing animals into groups by their shared traits is the main way naturalists make sense of this diversity and trace the relationships among species.

Frequently asked questions

What do vultures eat?

Vultures are scavengers that feed mainly on the bodies of dead animals, helping to remove carcasses from the landscape.

How does a viper deliver venom?

A viper has long, hinged fangs that fold back in the mouth and swing forward to strike, injecting venom to subdue prey.

What is a vicuna?

The vicuna is a slender wild relative of the llama and camel that lives in the high grasslands of the South American Andes and produces very fine wool.