Surplus killing

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A stoat surplus killing chipmunks. Ernest Thompson Seton, 1909. Stoat and chipmunks.png
A stoat surplus killing chipmunks. Ernest Thompson Seton, 1909.
Multiple sheep kill by a cougar Multiple sheep kill.jpg
Multiple sheep kill by a cougar

Surplus killing, also known as excessive killing, henhouse syndrome, [1] [2] or overkill, [3] is a common behavior exhibited by predators, in which they kill more prey than they can immediately eat and then they either cache or they abandon the remainder. The term was invented by Dutch biologist Hans Kruuk after studying spotted hyenas in Africa [4] and red foxes in England. [5] [6] Some of the animals which have been observed engaging in surplus killing include zooplankton, damselfly naiads, predaceous mites, martens, weasels, honey badgers, wolves, jaguars, orcas, red foxes, leopards, lions, spotted hyenas, spiders, brown bears, [7] American black bears, polar bears, coyotes, lynx, mink, raccoons, dogs, and humans.[ citation needed ]


There are many documented examples of predators exhibiting surplus killing. For example, researchers in Canada's Northwest Territories once found the bodies of 34 neonatal caribou calves that had been killed by wolves and scattered—some half-eaten and some completely untouched—over 3 square kilometres (1.2 sq mi). [8]

In Tasmania, in a single dog attack, 58 penguins were killed. [9] In Australia, over several days a single fox once killed around 74 penguins, eating almost nothing. [10] One leopard in Cape Province, South Africa killed 51 sheep and lambs in a single incident. [11] Similarly, two caracal in Cape Province killed 22 sheep in one night, eating only part of the buttock of one carcass. [12] Up to 19 spotted hyenas once killed 82 Thomson's gazelle and badly injured 27, eating just 16%. [1]

In late autumn, least weasels often surplus kill vole and then dig them up and eat them on winter days when it is too cold to hunt. [1] Surplus killing by wolves has mainly been observed when snow is unusually deep in late winter or early spring, [13] and the wolves have frequently cached their prey for eating days or weeks later. On February 7, 1991, in Denali National Park, six wolves killed at least 17 caribou and left many untouched. By February 13, 30–95% of each carcass had been eaten or cached, and by April 16, several had been dug up and fed upon again. [14] In March 2016, a Wyoming wolf pack of 9 wolves were found to have slaughtered 19 elk. John Lund, of the Wyoming Game and Fish Department, claimed to have never documented surplus killings to that extreme. [15] In Florida, through laboratory experiments, cases of surplus killing in larvae of the predatory midge Corethrella appendiculata against specific larval stages of different species of mosquitoes of the genus Toxorhynchites have been documented. [16]

In surplus killing, predators eat only the most-preferred animals and animal parts. Bears engaging in surplus killing of salmon are likelier to eat unspawned fish because of their higher muscle quality, and high-energy parts such as brains and eggs. [1] Surplus killing can deplete the overall food supply, waste predator energy and risk them being injured. Nonetheless, researchers say animals surplus kill whenever they can, in order to procure food for offspring and others, to gain valuable killing experience, and to create the opportunity to eat the carcass later when they are hungry again. [1] [17]

See also

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Coyote Species of canine native to North America

The coyote is a species of canine native to North America. It is smaller than its close relative, the wolf, and slightly smaller than the closely related eastern wolf and red wolf. It fills much of the same ecological niche as the golden jackal does in Eurasia, though it is larger and more predatory, and it is sometimes called the American jackal by zoologists. Other names for the species, largely historical, include the prairie wolf and the brush wolf.

Hyena family of carnivoran mammal

Hyenas or hyaenas are feliform carnivoran mammals of the family Hyaenidae. With only four extant species, it is the fifth-smallest biological family in the Carnivora, and one of the smallest in the class Mammalia. Despite their low diversity, hyenas are unique and vital components of most African ecosystems.

Wolf Type of canine

The wolf, also known as the gray wolf or grey wolf, is a large canine native to Eurasia and North America. More than thirty subspecies of Canis lupus have been recognized, and gray wolves, as colloquially understood, comprise non-domestic/feral subspecies. The wolf is the largest extant member of Canidae, males averaging 40 kg (88 lb) and females 37 kg (82 lb). Wolves measure 105–160 cm (41–63 in) in length and 80–85 cm (31–33 in) at shoulder height. The wolf is also distinguished from other Canis species by its less pointed ears and muzzle, as well as a shorter torso and a longer tail. The wolf is nonetheless related closely enough to smaller Canis species, such as the coyote and the golden jackal, to produce fertile hybrids with them. The banded fur of a wolf is usually mottled white, brown, gray, and black, although subspecies in the arctic region may be nearly all white.

Wolverine Species of the family Mustelidae

The wolverine, Gulo gulo, also referred to as the glutton, carcajou, skunk bear, or quickhatch, is the largest land-dwelling species of the family Mustelidae. It is a stocky and muscular carnivore, more closely resembling a small bear than other mustelids. A solitary animal, it has a reputation for ferocity and strength out of proportion to its size, with the documented ability to kill prey many times larger than itself.

Predation A biological interaction where a predator kills and eats a prey organism

Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation and parasitoidism. It is distinct from scavenging on dead prey, though many predators also scavenge; it overlaps with herbivory, as seed predators and destructive frugivores are predators.

Caracal Small wild cat

The caracal is a medium-sized wild cat native to Africa, the Middle East, Central Asia, and India. It is characterised by a robust build, long legs, a short face, long tufted ears, and long canine teeth. Its coat is uniformly reddish tan or sandy, while the ventral parts are lighter with small reddish markings. It reaches 40–50 cm (16–20 in) at the shoulder and weighs 8–19 kg (18–42 lb). It was first scientifically described by German naturalist Johann Christian Daniel von Schreber in 1776. Three subspecies are recognised.

Striped hyena Species of hyena

The striped hyena is a species of hyena native to North and East Africa, the Middle East, the Caucasus, Central Asia and the Indian subcontinent. It is listed by the IUCN as near-threatened, as the global population is estimated to be under 10,000 mature individuals which continues to experience deliberate and incidental persecution along with a decrease in its prey base such that it may come close to meeting a continuing decline of 10% over the next three generations. It is also the national animal of Lebanon.

Brown hyena

The brown hyena, also called strandwolf, is a species of hyena found in Namibia, Botswana, western and southern Zimbabwe, southern Mozambique and South Africa. It is currently the rarest species of hyena. The largest remaining brown hyena population is located in the southern Kalahari Desert and coastal areas in Southwest Africa. The global population of brown hyena is estimated by IUCN at a number between 4,000 and 10,000 and its conservation status is marked as near threatened in the IUCN Red List.

Spotted hyena Species of hyena

The spotted hyena, also known as the laughing hyena, is a hyena species, currently classed as the sole extant member of the genus Crocuta, native to sub-Saharan Africa. It is listed as being of least concern by the IUCN on account of its widespread range and large numbers estimated between 27,000 and 47,000 individuals. The species is, however, experiencing declines outside of protected areas due to habitat loss and poaching. The species may have originated in Asia, and once ranged throughout Europe for at least one million years until the end of the Late Pleistocene. The spotted hyena is the largest known member of the Hyaenidae, and is further physically distinguished from other species by its vaguely bear-like build, its rounded ears, its less prominent mane, its spotted pelt, its more dual purposed dentition, its fewer nipples and the presence of a pseudo-penis in the female. It is the only mammalian species to lack an external vaginal opening.


Machairodontinae is an extinct subfamily of carnivoran mammals of the family Felidae. They were found in Asia, Africa, North America, South America, and Europe from the Miocene to Pleistocene living from about 16 million until about 11,000 years ago.

A wolf in sheep's clothing is an idiom of Biblical origin used to describe those playing a role contrary to their real character with whom contact is dangerous, particularly false teachers. Much later, the idiom has been applied by zoologists to varying kinds of predatory behaviour. A fable based on it has been falsely credited to Aesop and is now numbered 451 in the Perry Index. The confusion has arisen from the similarity of the theme with fables of Aesop concerning wolves that are mistakenly trusted by shepherds; the moral drawn from these is that one's basic nature eventually shows through the disguise.

Man-eater is a colloquial term for an individual animal that preys on humans as a pattern of hunting behavior. This does not include the scavenging of corpses, a single attack born of opportunity or desperate hunger, or the incidental eating of a human that the animal has killed in self-defense. However, all three cases may habituate an animal to eating human flesh or to attacking humans, and may foster the development of man-eating behavior.

Domestic sheep predation

Along with parasites and disease, predation is a threat to sheep health and consequently to the profitability of sheep raising. Sheep have very little ability to defend themselves, even when compared with other prey species kept as livestock. Even if sheep are not directly bitten or survive an attack, they may die from panic or from injuries sustained.

Killing for a Living is a nature documentary show that debuted on BBC and Discovery Channel in 1993, and later repeated on Animal Planet. It was produced by Wildvision Production for BBC Worldwide in association with The Discovery Channel. The documentary showcased various predators and the way they capture and kill their victims. The series was narrated by Anthony Hopkins from episode 1-3 and John Shrapnel from episode 4 onwards.

Avivore Animal that preys on and eats birds

An avivore is a specialized predator of birds, with birds making up a large proportion of its diet. Such bird-eating animals come from a range of groups.

Grizzly bear Subspecies of mammal

The grizzly bear, also known as the North American brown bear or simply grizzly, is a large population or subspecies of the brown bear inhabiting North America.

African golden wolf

The African golden wolf is a canine native to North Africa and the Horn of Africa. It is the descendant of a genetically admixed canid of 72% gray wolf and 28% Ethiopian wolf ancestry. It occurs in Senegal, Nigeria, Chad, Morocco, Algeria, Tunisia, Libya, Kenya, Egypt, and Tanzania. It is listed as least concern on the IUCN Red List. In the Atlas Mountains, it was sighted in elevations as high as 1,800 m (5,900 ft). It is primarily a predator, targeting invertebrates and mammals as large as gazelle fawns, though larger animals are sometimes taken. Its diet also includes animal carcasses, human refuse, and fruit. The African golden wolf is a monogamous and territorial species; offspring remain with the family to assist in raising their parents' younger pups.

Pursuit predation

Pursuit predation is a form of predation in which predators give chase to fleeing prey. The chase can be initiated either by the predator or by the prey, should the prey be alerted to a predator's presence and attempt to flee before the predator gives chase. The chase ends when either the predator captures and consumes the prey, or the prey escapes. Pursuit predation is typically observed in carnivorous species within the kingdom Animalia, with some iconic examples being cheetahs, lions, and wolves.

Dietary biology of the brown bear

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  1. 1 2 3 4 5 Mills, L. Scott. Conservation of wildlife populations: demography, genetics, and management (2nd ed.). Hoboken, NJ: Wiley-Blackwell. p. 148. ISBN   9780470671504.
  2. Moskowitz, David. Wolves in the Land of Salmon. Timber Press. p. 144. ISBN   1604692278.
  3. Mysterud, Ivar (1980). "Bear Management and Sheep Husbandry in Norway, with a Discussion of Predatory Behavior Significant for Evaluation of Livestock Losses". Bears: Their Biology and Management. 4: 233–241. doi:10.2307/3872873. ISSN   1936-0614.
  4. Kruuk, Hans (1972). The Spotted Hyena: A study of predation and social behaviour . p.  335. ISBN   0-563-20844-9.
  5. Macdonald, David (1987). Running with the Fox. p. 224. ISBN   0-04-440199-X.
  6. Hans Kruuk: Surplus killing by carnivores Journal of Zoology 1972
  7. "Far North Grizzlies Develop Taste for Muskoxen, Alaska Science Forum". June 21, 2011. Archived from the original on August 7, 2011.
  8. Mech, edited by L. David; Boitani, Luigi (2003). Wolves: behavior, ecology, and conservation. Chicago [u.a.]: Univ. of Chicago Press. p. 145. ISBN   9780226516967.CS1 maint: extra text: authors list (link)
  9. Adamczyk, Ed (2018-10-17). "Dog attack kills 58 penguins in Tasmania". UPI. Retrieved 2020-04-04.
  10. Peacock, Sue (2017-08-10). "Penguins killed in fox attack on Victoria's Middle Island". ABC News. Retrieved 2019-09-26.
  11. Stuart, C. T. (1986). "The incidence of surplus killing by Panthera pardus and Felis caracal in Cape Province, South Africa". Mammalia. 50 (4): 556–558. doi:10.1515/mamm.1986.50.4.553. ISSN   0025-1461.
  12. Skinner, J. D. (1979). "Feeding behaviour in Caracal Felis caracal". Journal of Zoology. 189 (4): 523–525. doi:10.1111/j.1469-7998.1979.tb03979.x.
  13. Henryk Okarma, Sven Herzog: Handbuch Wolf. Kosmos-Verlag, Stuttgart 2019, page 148
  14. Moskowitz, David. Wolves in the Land of Salmon. Timber Press. p. 145. ISBN   1604692278.
  15. "Wyoming wolf pack kills 19 elk in rare 'surplus killing'". Archived from the original on 2016-04-04. Retrieved 2016-03-25.
  16. L.P. Lounibos, S. Mahkni, B.W.Alto, B. Kesavaraju (Mar 2008). "Surplus Killing by Predatory Larvae of Corethrella appendiculata: Prepupal Timing and Site-Specific Attack on Mosquito Prey". Journal of insects behaviour. 21 (2): 47–54. doi:10.1007/s10905-007-9103-2. PMC   2600435 .CS1 maint: multiple names: authors list (link)
  17. Hansen, Kevin (2006). Bobcat: master of survival ([Online-Ausg.] ed.). New York: Oxford University Press. pp.  114. ISBN   0195183037.