Scavengers

Scavengers are animals that consume dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a herbivorous feeding behavior. Scavengers play an important role in the ecosystem by consuming dead animal and plant material. ''Decomposers'' and detritivores complete this process, by consuming the remains left by scavengers.

Scavengers aid in overcoming fluctuations of food resources in the environment. The process and rate of scavenging is affected by both biotic and abiotic factors, such as carcass size, habitat, temperature, and seasons.

Etymology

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).

Types of scavengers (animals)

Obligate scavenging (subsisting entirely or mainly on dead animals) is rare among vertebrates, due to the difficulty of finding enough carrion without expending too much energy.

Well-known invertebrate scavengers of animal material include burying beetles and blowflies, which are obligate scavengers, and yellowjackets. Fly larvae are also common scavengers for organic materials at the bottom of freshwater bodies. For example, ''Tokunagayusurika akamusi'' is a species of midge fly whose larvae live as obligate scavengers at the bottom of lakes and whose adults almost never feed and only live up to a few weeks.

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 and jackals, but also animals rarely thought of as scavengers, such as African lions, leopards, 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 victim, rather than a perpetrator). 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. Scavenging wild dogs and crows frequently exploit roadkill.

Scavengers of dead plant material include termites that build nests in grasslands and then collect dead plant material for consumption within the nest. The interaction between scavenging animals and humans is seen today most commonly in suburban settings with animals such as opossums, polecats and raccoons. In some African towns and villages, scavenging from hyenas is also common.

In the prehistoric eras, the species ''Tyrannosaurus rex'' may have been an apex predator, preying upon hadrosaurs, ceratopsians, and possibly juvenile sauropods, although some experts have suggested the dinosaur was primarily a scavenger. The debate about whether ''Tyrannosaurus'' was an apex predator or scavenger was among the longest ongoing feuds in paleontology; however, most scientists now agree that ''Tyrannosaurus'' was an opportunistic carnivore, acting mostly as a predator but also scavenging when it could sense it. Recent research also shows that while an adult ''Tyrannosaurus rex'' would energetically gain little through scavenging, smaller theropods of approximately might have gained levels similar to those of hyenas, though not enough for them to rely on scavenging.

Other research suggests that carcasses of giant sauropods may have made scavenging much more profitable to carnivores than it is now. For example, a single 40 tonne ''Apatosaurus'' carcass would have been worth roughly 6 years of calories for an average allosaur. As a result of this resource oversupply, it is possible that some theropods evolved to get most of their calories by scavenging giant sauropod carcasses, and may not have needed to consistently hunt in order to survive. The same study suggested that theropods in relatively sauropod-free environments, such as tyrannosaurs, were not exposed to the same type of carrion oversupply, and were therefore forced to hunt in order to survive. There are also an info that Megalodon, Ceratosaurus, Andrewsarchus and some more prehistoric animals were scavengers.

Animals which consume feces, such as dung beetles, are referred to as coprovores. Animals that collect small particles of dead organic material of both animal and plant origin are referred to as detritivores.

Ecological function

Scavengers play a fundamental role in the environment through the removal of decaying organisms, serving as a natural sanitation service. While microscopic and invertebrate decomposer