A habitat is the natural home where a plant or animal lives and finds everything it needs to survive: food, water, shelter, and space to grow or raise young. A polar bear's habitat is the Arctic ice, where it hunts seals and raises cubs. A cactus's habitat is the desert, where it stores water in its thick stem and thrives in sandy soil and blazing heat.

Different creatures need different habitats. Trout need cold, clear streams with plenty of oxygen. Frogs need ponds or wetlands. Oak trees need deep soil and moderate rainfall. Each habitat provides exactly what its residents require, which is why you won't find penguins in the Sahara or camels in Antarctica.

When people say an animal's natural habitat, they mean where it evolved to live over millions of years, as opposed to living in a zoo or aquarium. Scientists study habitats to understand how plants and animals depend on their surroundings. When forests are cleared or wetlands are drained, creatures lose their habitats and must find new places to live or face extinction. Protecting habitats means preserving not just the animals themselves, but the entire environment they need to thrive.