Animals and Area

    One of the factors that determine the distribution of life forms is the availability of the resources necessary for life.

   In the desert, for example, the limiting factor is water: there are areas of bare earth between the plants. Because there are few plants, animals are small and many of them are cold blooded: insects and reptiles survive on very little food, though a few specially adapted mammals, such as the kangaroo rat, wait out the heat in burrows and search for seeds at night.