Animals What? -insects, birds, fish and mammals Damages: -valuable crops -spread diseases Difficulties: -tend to be small -mature and reproduce rapidly -become large populations		Animal pests include insects, fish, birds, and mammals. Most animal pests feed on vegetation like crops, trees, and grains and some spread diseases. In small numbers, they are usually not a problem. However, certain animal pests are able to mature and reproduce rapidly. For example, rats and houseflies reproduce many times in a single year. This is especially true if they have an adequate food supply. Consequently, small numbers of pests can soon become large, unmanageable populations.