Animals of the World

The animal kingdom spans an extraordinary range of forms, and naming and grouping animals helps make sense of that diversity. Birds, for instance, are warm-blooded, feathered animals, most of which can fly; owls are nocturnal birds of prey with keen hearing and silent flight that hunt small animals at night. Amphibians such as newts pass through an aquatic larval stage and have moist skin sensitive to their surroundings.

Mammals add further variety. The orangutan is a large, tree-dwelling ape native to the rainforests of Southeast Asia, an intelligent primate now endangered through the loss of its forest home. Marine mammals such as the narwhal, a whale of Arctic waters distinguished by the male's long spiral tusk, show how mammals have adapted to life in the sea while still breathing air.

Invertebrates make up the largest share of animal species. The octopus, a soft-bodied marine mollusk with eight arms, is remarkably intelligent and able to change color and texture to blend with its surroundings. From insects and arachnids to mollusks and marine creatures, invertebrates fill countless roles in ecosystems, underscoring how broad and varied the animal world truly is. Grouping animals by their shared features remains the main way scientists make sense of this enormous diversity and trace how species are related.

Frequently asked questions

How do owls hunt at night?

Owls are nocturnal birds of prey with very keen hearing and eyesight and soft feathers that allow nearly silent flight, helping them catch prey in the dark.

What is special about the narwhal?

The narwhal is an Arctic whale in which the male has a long, spiral tusk, which is actually an elongated tooth.

Why is the octopus considered intelligent?

Octopuses can solve problems, use their flexible arms skillfully, and change color and texture to camouflage themselves, showing advanced behavior for an invertebrate.