Cannibalism

A slug, Arion vulgaris, eating a dead individual of the same species

Cannibalism is the act of consuming another individual of the same species as food. Cannibalism is a common ecological interaction in the animal kingdom and has been recorded in more than 1,500 species.[1] Human cannibalism is well documented, both in ancient and in recent times.[2]

The rate of cannibalism increases in nutritionally poor environments as individuals turn to conspecifics as an additional food source.[3] Cannibalism regulates population numbers, whereby resources such as food, shelter and territory become more readily available with the decrease of potential competition. Although it may benefit the individual, it has been shown that the presence of cannibalism decreases the expected survival rate of the whole population and increases the risk of consuming a relative.[3] Other negative effects may include the increased risk of pathogen transmission as the encounter rate of hosts increases.[4] Cannibalism, however, does not—as once believed—occur only as a result of extreme food shortage or of artificial/unnatural conditions, but may also occur under natural conditions in a variety of species.[1][5][6]

Cannibalism is prevalent in aquatic ecosystems, in which up to approximately 90% of the organisms[vague] engage in cannibalistic activity at some point in their life-cycle.[vague][7] Cannibalism is not restricted to carnivorous species: it also occurs in herbivores and in detritivores.[vague][5] Sexual cannibalism normally involves the consumption of the male by the female individual before, during or after copulation.[3] Other forms of cannibalism include size-structured cannibalism and intrauterine cannibalism.

Behavioral, physiological and morphological adaptations have evolved to decrease the rate of cannibalism in individual species.[3]

  1. ^ a b Polis, G. A. (1981). "The Evolution and Dynamics of Intraspecific Predation". Annual Review of Ecology and Systematics. 12: 225–251. doi:10.1146/annurev.es.12.110181.001301.
  2. ^ Goldman, Laurence, ed. (1999). The Anthropology of Cannibalism. Greenwood Publishing Group. ISBN 978-0-89789-596-5.
  3. ^ a b c d Elgar, M.A. & Crespi, B.J. (1992) Cannibalism: ecology and evolution among diverse taxa, Oxford University Press, Oxford [England]; New York.
  4. ^ Rudolf, V. H.; Antonovics, J. (2007). "Disease transmission by cannibalism: Rare event or common occurrence?". Proceedings. Biological Sciences. 274 (1614): 1205–10. doi:10.1098/rspb.2006.0449. PMC 2189571. PMID 17327205.
  5. ^ a b Fox, L. R. (1975). "Cannibalism in Natural Populations". Annual Review of Ecology and Systematics. 6: 87–106. doi:10.1146/annurev.es.06.110175.000511.
  6. ^ Elgar, M. A. and Crespi, B. J. (eds) (1992) Cannibalism: Ecology and evolution among diverse taxa. Oxford University Press, New York.
  7. ^ Rudolf, Volker H. W. (2007). The Influence of Cannibalism and Size Structure on the Dynamics of Aquatic Communities. University of Virginia. p. 2. Archived from the original on 16 April 2021. Retrieved 23 February 2019. Cannibalism is a common ecological interaction in the animal kingdom, and it is ubiquitous in aquatic and terrestrial food webs [...].