Zoo is a place where people keep and display animals. Visiting zoos is a popular recreational and educational activity throughout the world. Almost every large city has at least one zoo, and many smaller communities also have one. Many zoos have beautiful gardens and treelined paths leading from one animal display to another. The word zoo is short for zoological garden.
Zoos vary in the type of animals they keep. Many large zoos keep mammals, birds, reptiles, and fish from all over the world. Some even have collections of interesting insects. Smaller zoos may have animals from just one part of the world, or just one type of animal. Zoos that have only fish and aquatic mammals, which live in water, are called aquariums. Some zoos display only animals from the region where the zoo is located.
Zoos range in size from hundreds of acres or hectares to only a few. But size alone does not determine the quality or importance of a zoo. The best zoos are those that have healthy, well-tended animals and displays that help visitors learn about each animal's natural behavior and its role in the environment.
Modern zoos have become refuges for some species (types) of animals that are in danger of extinction (dying out) in the wild. Many human activities threaten the survival of wild species, especially the destruction of habitats (natural environments). Most animals are specially suited to live in a certain environment and cannot survive when their habitat is destroyed. Zoos are becoming increasingly active in the struggle to save the world's vanishing wildlife.
