They also use materials made inside their own bodies such as silk and beeswax. Some animals such as beavers build their own homes. Some animals such as woodpeckers live in homes built by other animals. Shelled animals like turtles carry their homes with them. Animals may live in large colonies, in small family groups, or alone.
Humans also live in extended groups and many different kinds of family arrangements.
The one factor that determines whether or not a place can be a habitat is the presence of green plants. When you think about it, all animals depend on green plants for food because only green plants can make their own food. They use sunshine, water, and nutrients from the soil to provide themselves with nourishment. The process is called photosynthesis. Some animals eat green plants, some animals eat animals that eat green plants, and some animals eat both.