A predator is an organism that hunts and eats its prey. All predators are heterotrophs, meaning they must consume the tissues of other organisms to fuel their own growth and reproduction. The most common use of the term is to describe the many types of carnivorous animals that catch, kill, and eat other animals. There is a great diversity of such predatory animals, ranging in size from small arthropods such as tiny soil mites that eat other mites and springtails, to large mammalian carnivores such as lions and orcas, living in cohesive social groups and collectively hunting, killing, and feeding on prey that can weigh more than a ton.
Most animal predators kill their prey and then eat it. However, so-called micropredators only consume part of large prey animals, and they do not necessarily kill their quarry. Female mosquitoes, for example, are micropredators that seek out large prey animals for the purpose of obtaining a blood meal, in the process aggravating, but not killing their prey. If this sort of feeding relationship is an obligate one for the micropredator, it is referred to as parasitism.
Herbivory is another type of predation, in which animals seek out and consume a prey of plant tissues, sometimes killing the plant in the process. In some cases, only specific plant tissues or organs are consumed by the herbivore, and ecologists sometimes refer to such feeding
relationships as, for example, seed predation or leaf predation.
Most predators are animals, but a few others are plants and fungi. For example, carnivorous plants such as pitcher plants and sundews are morphologically adapted to attracting and trapping small arthropods. The prey is then digested by enzymes secreted for the purpose, and some of the nutrients are assimilated by the predatory plant. Carnivorous plants usually grow in nutrient-poor habitats, and this is the basis in natural selection for the evolution of this unusual type of predation. A few types of fungi are also predatory, trapping small nematodes using various anatomical devices, such as sticky knobs or branches, and tiny constrictive rings that close when nematodes try to move through. Once a nematode is caught, fungal hyphae surround and penetrate their victim, and absorb its nutrients.