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Scavengers are animals that feed on dead and decaying organic matter. Often the term is used to describe the consumption of carrion, the bodies of animals that have died from causes other than predation or the bodies of animals that have been killed by other predators. However, the term is also used to describe animals that feed on rotting plant matter or waste.
and burying beetles are examples of scavengers that feed on carrion, pink bud moth and stag beetle larvae are examples of scavengers that feed on rotting plant matter, and and squirrels are examples of scavengers that feed on refuse. Carrion-eating scavengers are called . (2025). 9780191826320, Oxford University Press. ISBN 9780191826320 See also:
Scavengers play an important role in by preventing the accumulation of decaying matter and helping to recycle nutrients. and complete this process, by consuming the remains left by scavengers.
The ability of an animal to scavenge helps it overcome fluctuations in food availability. The process and rate at which dead plant and animal material is scavenged is affected by both Biotic component and abiotic factors, such as plant species, carcass size, habitat, temperature, moisture levels, and seasons.
Most of the vertebrates that eat carrion are facultative scavengers, capable of obtaining food via predation or other methods, and eating carrion opportunistically. Many large that hunt regularly, such as and , but also animals rarely thought of as scavengers, such as African , , and gray wolf will scavenge if given the chance. They may also use their size and ferocity to intimidate the original hunters into abandoning their kills (the cheetah is a notable victim, rather than a perpetrator). (2025). 9780226779997, The University of Chicago Press. ISBN 9780226779997 , Carrion crow and Eurasian magpie frequently scavenge roadkill.
Aquatic and semi-aquatic vertebrates feed on carrion too. Carrion-eating scavengers found in marine settings include hagfish, great white sharks, northern wolffish and abyssal grenadiers, and carrion-eating scavengers found in freshwater settings include American alligators, and common midwife toads.
, and bone skipper flies are examples of obligately necrophagous invertebrates. They are all dependent on carrion during the larval stages of their life cycles. Adult burying beetles and vulture bees feed on carrion too. Other invertebrates, such as Calliphoridae, Sarcophagidae and , also feed on carrion but are not reliant on it for survival. Blow fly and flesh fly larvae can feed on excrement, and some species, for example, Chrysomya putoria and Sarcophaga crassipalpis, can feed on living tissue. (2025). 9780849381201, CRC Press. ISBN 9780849381201 Also, can hunt and other insects and feed on nectar, sap and fruit.
In addition to the terrestrial examples above, many aquatic invertebrates consume carrion. The common octopus, Carcinus maenas and Luidia ciliaris are all marine invertebrates that feed on carrion, and the ribbon leech Erpobdella obscura and red swamp crayfish are freshwater invertebrates that feed on carrion.
Pink bud moth larvae (also known as pink scavenger caterpillars) are facultative scavengers of dead plant material, feeding on rotting fruits, decaying flowers and leaves, but also the fruits and grains of live plants. Termites are facultative scavengers too. Termites feed on dead trees and wood, but also live plants and detritus such as humus and excrement. Additional examples of facultative scavengers in this category are darkling beetles (also known as tenebrionids) and Opogona sacchari larvae.
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.
Scavenging unites animals which normally would not come into contact, and results in the formation of highly structured and complex communities which engage in nonrandom interactions. Scavenging communities function in the redistribution of energy obtained from carcasses and reducing diseases associated with decomposition. Oftentimes, scavenger communities differ in consistency due to carcass size and carcass types, as well as by seasonal effects as consequence of differing invertebrate and microbial activity.
Competition for carrion results in the inclusion or exclusion of certain scavengers from access to carrion, shaping the scavenger community. When carrion decomposes at a slower rate during cooler seasons, competitions between scavengers decrease, while the number of scavenger species present increases.
Alterations in scavenging communities may result in drastic changes to the scavenging community in general, reduce ecosystem services and have detrimental effects on animal and humans. The reintroduction of gray wolves ( Canis lupus) into Yellowstone National Park in the United States caused drastic changes to the prevalent scavenging community, resulting in the provision of carrion to many mammalian and avian species. Likewise, the reduction of vulture species in India lead to the increase of opportunistic species such as feral dogs and rats. The presence of both species at carcasses resulted in the increase of diseases such as rabies and bubonic plague in wildlife and livestock, as feral dogs and rats are transmitters of such diseases. Furthermore, the decline of vulture populations in India has been linked to the increased rates of anthrax in humans due to the handling and ingestion of infected livestock carcasses. An increase of disease transmission has been observed in mammalian scavengers in Kenya due to the decrease in vulture populations in the area, as the decrease in vulture populations resulted in an increase of the number of mammalian scavengers at a given carcass along with the time spent at a carcass.
A major vector of transmission of diseases are various bird species, with outbreak being influenced by such carrier birds and their environment. An avian cholera outbreak from 2006 to 2007 off the coast Newfoundland, Canada resulted in the mortality of many marine bird species. The transmission, perpetuation and spread of the outbreak was mainly restricted to gull species who scavenge for food in the area. Similarly, an increase of transmission of avian influenza virus to chickens by domestic ducks from Indonesian farms permitted to scavenge surrounding areas was observed in 2007. The scavenging of ducks in rice paddy fields in particular resulted in increased contact with other bird species feeding on leftover rice, which may have contributed to increased infection and transmission of the avian influenza virus. The domestic ducks may not have demonstrated symptoms of infection themselves, though were observed to excrete high concentrations of the avian influenza virus.
In Tibetan Buddhism, the practice of excarnation—that is, the exposure of dead human bodies to carrion birds and/or other scavenging animals—is the distinctive characteristic of sky burial, which involves the dismemberment of human of whom the remains are fed to , and traditionally the main funerary rite (alongside cremation) used to dispose of the human body. A similar funerary practice that features excarnation can be found in Zoroastrianism; in order to prevent the pollution of the sacred elements (fire, earth, and water) from contact with decomposing bodies, human cadavers are exposed on the Towers of Silence to be eaten by vultures and wild dogs.
Studies in behavioral ecology and Ecology epidemiology have shown that cannibalistic necrophagy, although rare, has been observed as a survival behavior in several social species, including anatomically modern humans; however, episodes of human cannibalism occur rarely in most human societies. Many instances have occurred in human history, especially in times of war and famine, where necrophagy and human cannibalism emerged as a survival behavior, although report the usage of ritual cannibalism among funerary practices and as the preferred means of disposal of the dead in some tribal societies.
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