A limiting factor is any one of the basic needs (food, water, suitable habitat) determining the maximum size of an animal population. As an example, during the summer rains in the Sonoran desert millions of spade foot toads hatch in temporary waterholes. Relatively few of them live to maturity. They can be limited by all 3 factors. For one puddle, there may be so many that all the available food is consumed. At another, nearby ravens may feast on the babies because they lack a place to hide. A third puddle might dry up before the young mature.