Wildlife is in danger...

what makes wildlife become extinct by time to time...??
well,,

Many species of wildlife are endangered; some have become extinct due to the destruction of the animals' habitats from agricultural, industrial, and urban developments, as well as having to compete with humans for food. Several hundred species of animals still face the danger of extinction. Such wildlife include the grizzly bear, the jaguar, the panda, the squirrel monkey, the fox, the tiger, and the whale.