Necrophagy

Scavenging is both a carnivorous and a herbivorous feeding behavior in which the scavenger feeds on dead animal and plant material present in its habitat. The eating of carrion from the same species is referred to as cannibalism. Scavengers play an important role in the ecosystem by consuming the dead animal and plant material. Decomposers and detritivores complete this process, by consuming the remains left by scavengers.

Scavenger is an alteration of scavager, from Middle English skawager meaning "customs collector", from skawage meaning "customs", from Old North French escauwage meaning "inspection", from schauwer meaning "to inspect", of Germanic origin; akin to Old English scēawian and German schauen meaning "to look at", and modern English "show" (with semantic drift).

Obligate scavenging is very rare in the animal kingdom, due to the difficulty of finding enough carrion without expending too much energy. In vertebrates, only vultures and possibly some pterosaurs are obligate scavengers, as terrestrial soaring flyers are the only animals able to find enough carrion.

Well-known invertebrate scavengers of animal material include burying beetles and blowflies, which are obligate scavengers, and yellowjackets.

Most scavenging animals are facultative scavengers that gain most of their food through other methods, especially predation. Many large carnivores that hunt regularly, such as hyenas, but also animals rarely thought of as scavengers, such as African lions, leopards, jackals, and wolves will scavenge if given the chance. They may also use their size and ferocity to intimidate the original hunters (the cheetah is a notable exception). Almost all scavengers above insect size are predators and will hunt if not enough carrion is available, as few ecosystems provide enough dead animals year-round to keep its scavengers fed on that alone. Scavenger wild dogs and crows frequently exploit roadkill.

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Wikipedia