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[[Ficheiro:Mononchidae eating a Mononchidae 1.jpg|200px|miniatura|Un [[nematodo]] [[Mononchidae]] comendo outro Mononchidae.]]
O canibalismo estruturado polo tamaño é aquel na que os individuos máis maduros, grandes e vellos comen a outros máis novos da súa especie. Nas poboacións estruturadas por tamaño (nas que estas están formadas por individuos de varios tamaños, idades e graos de madurez), o canibalismo pode ser responsable do 8% (no roedor ''[[Urocitellus beldingi]]'') ao 95% (en larvas de [[libélula]]s) da mortalidade total,<ref>G. A. Polis, The evolution and dynamics of intraspecific predation. Annual Review of Ecology and Systematics 12, 225-251 (1981)</ref> makingpolo itque aque significantun andfactor importantimportatne factorna dinámica fordas populationpoboacións<ref>David Claessen, A. M. De Roos, and L. Persson, Population dynamic theory of size-dependent cannibalism. Proceedings of the Royal Society of London Series B-Biological Sciences 271 (1537), 333-340 (2004)</ref> ande communityda dynamicscomunidade.<ref>V. H. W. Rudolf, Consequences of stage-structured predators: Cannibalism, behavioral effects and trophic cascades. Ecology 88, 2991-3003 (2007)</ref>
O caniblismocanibalismo estruturado por tamaño foi observado comunmente na ntureza en varios [[taxon]]s. Un exemplo en vertebrados son os [[chimpancé]]s, nos que se observou que grupos de machos adultos atacaban e comían crías.<ref>A. C. Arcadi and R. W. Wrangham, Infanticide in chimpanzees: Review of cases and a new within-group observation from the Kanyawara study group in [[Kibale National Park]]. Primates 40 (2), 337-351 (1999).</ref><ref>M. L. Wilson, W. R. Wallauer, and A. E. Pusey, New cases of intergroup violence among chimpanzees in Gombe National Park, Tanzania. International Journal Of Primatology 25 (3), 523-549 (2004).</ref><ref>D. P. Watts, J. C. Mitani, and H. M. Sherrow, New cases of inter-community infanticide by male chimpanzees at Ngogo, Kibale National Park, Uganda. Primates 43 (4), 263-270 (2002)</ref>
=== Canibalismo filial ===
O canibalismo filial é un tipo específico de canibalismo estruturado polo tamaño no cal os adultos comen a súa propia proxenie.<ref name="Rohwer, S 1978">Rohwer, S. 1978. Parent Cannibalism of Offspring and Egg Raiding as a Courtship Strategy. American Naturalist 112:429-440.</ref> Though most often thought of as parents eating live young, filial cannibalism includes parental consumption of [[Stillbirth|stillborn]] infants and [[miscarriage|miscarried]] fetuses as well as infertile and still-incubating eggs. Vertebrate examples include [[pig]]s, where [[savaging]] accounts for a sizable percentage of total piglet deaths, and [[cat]]s.<ref>[http://www.messybeast.com/kill_kit.htm Hartwell, S, Cats that kill kittens]</ref> ▼
▲O canibalismo filial é un tipo específico de canibalismo estruturado polo tamaño no cal os adultos comen a súa propia proxenie.<ref name="Rohwer, S 1978">Rohwer, S. 1978. Parent Cannibalism of Offspring and Egg Raiding as a Courtship Strategy. American Naturalist 112:429-440.</ref> ThoughAínda mostque oftennormalmente thoughtse ofconsidera asque parentsconsisten eatingen liveque young,os filialpais cannibalismcoman includesos parentalfillos, consumptiontamén ofinclúe [[Stillbirth|stillborn]]o infantsconsumo andpolos [[miscarriage|miscarried]]pais fetusesde asfetos wellmortos ase infertileabortados ande still-incubatingovos eggs.infértiles Vertebrateou examplesaínda includeen [[ pigincubación dos ovos|incubación]] s,. whereExemplos en vertebrados son [[ savagingporco]] s, accountsnos forque aos sizableataques percentageda ofnai totalás pigletcrías deathssupoñen unha porcentaxe considerable das mortse de bácoros, andos [[ catgato]]s .,<ref>[http://www.messybeast.com/kill_kit.htm Hartwell, S, Cats that kill kittens]</ref> e o [[demo de Tasmania]], que come os recén nados que non conseguen chegar a algunha das catro tetas do animal.
Filial cannibalism is particularly common in [[teleost]] fishes, appearing in at least seventeen different families of teleosts.<ref>Manica, A. 2002. Filial cannibalism in teleost fish. Biological Reviews 77:261-277.</ref> Within this diverse group of fish, there have been many, variable explanations of the possible adaptive value of filial cannibalism. One of these is the energy-based hypothesis, which suggests that fish eat their offspring when they are low on energy as an investment in future reproductive success.<ref name="Rohwer, S 1978"/> This has been supported by experimental evidence, showing that male [[three-spined stickleback]]s,<ref name="Rohwer, S 1978"/><ref name="Mehlis, M. 2010">Mehlis, M., T. C. M. Bakker, L. Engqvist, and J. G. Frommen. 2010. To eat or not to eat: egg-based assessment of paternity triggers fine-tuned decisions about filial cannibalism. Proceedings of the Royal Society B-Biological Sciences 277:2627-2635.</ref><ref>Mehlis, M., T. C. M. Bakker, and J. G. Frommen. 2009. Nutritional benefits of filial cannibalism in three-spined sticklebacks (Gasterosteus aculeatus). Naturwissenschaften 96:399-403.</ref> male [[tessellated darter]]s,<ref>DeWoody, J. A., D. E. Fletcher, S. D. Wilkins, and J. C. Avise. 2001. Genetic documentation of filial cannibalism in nature. Proceedings of the National Academy of Sciences of the United States of America 98:5090-5092.</ref> and male [[sphinx blenny]] fish<ref>Kraak, S. B. M. 1996. Female preference and filial cannibalism in Aidablennius sphynx (Teleostei, Blenniidae); a combined field and laboratory study. Behavioural Processes 36:85-97.</ref> all consume or absorb their own eggs to maintain their physical conditions. In other words, when males of a fish species are low on energy, it might sometimes be beneficial for them to feed on their own offspring to survive and invest in future reproductive success. ▼
▲FilialO cannibalismcanibalismo isfilial particularlyé commonespecialmente incomún en peixes [[ teleostteleósteos]] fishes, appearinge indáse aten leastpolo seventeenmenos differentdezasete families of teleostsfamilias.<ref>Manica, A. 2002. Filial cannibalism in teleost fish. Biological Reviews 77:261-277.</ref> WithinDentro thisdeste diversediverso groupgrupo ofde fishpeixes, therepropuxéronse havemoitas beene many,variadas variableexplicacións explanationsdo ofposible thevalor possibleadaptativo adaptivedo value ofcanibalismo filial cannibalism. OneUnha ofdestas theseé isa thehipótese energy-basedbaseada hypothesisna enerxía, whichque suggestssuxire thatque fishos eatpeixes theircomen offspringos whenseus theydescendentes arecando lowteñen onpouca energyenerxía ascomo anun investmentinvestimento inpara o seu futureéxito reproductivereprodutivo successfuturo.<ref name="Rohwer, S 1978"/> ThisIsto hasfoi beenapoiado supportedpor byprobas experimentalexperimentais evidence,que mostrou showingque thatos malemachos de [[ three-spinedGasterosteus sticklebackaculeatus|espiñento]]s (''Gasterosteus aculeatus''),<ref name="Rohwer, S 1978"/><ref name="Mehlis, M. 2010">Mehlis, M., T. C. M. Bakker, L. Engqvist, and J. G. Frommen. 2010. To eat or not to eat: egg-based assessment of paternity triggers fine-tuned decisions about filial cannibalism. Proceedings of the Royal Society B-Biological Sciences 277:2627-2635.</ref><ref>Mehlis, M., T. C. M. Bakker, and J. G. Frommen. 2009. Nutritional benefits of filial cannibalism in three-spined sticklebacks (Gasterosteus aculeatus). Naturwissenschaften 96:399-403.</ref> maleos machos de ''[[ tessellatedEtheostoma darterolmstedi]] s,''<ref>DeWoody, J. A., D. E. Fletcher, S. D. Wilkins, and J. C. Avise. 2001. Genetic documentation of filial cannibalism in nature. Proceedings of the National Academy of Sciences of the United States of America 98:5090-5092.</ref> ande maleos machos de ''[[ sphinxAidablennius blennysphynx]] fish''<ref>Kraak, S. B. M. 1996. Female preference and filial cannibalism in Aidablennius sphynx (Teleostei, Blenniidae); a combined field and laboratory study. Behavioural Processes 36:85-97.</ref> allcomen consumeou orabsorben absorbos theirseus ownpropios eggsovos topara maintainmanter their physical conditions. In other words, when males of a fish species are low on energy, it might sometimes be beneficial for them to feed on their own offspring to survive and invest inas futuresúas reproductivecondicións successfísicas.
Another hypothesis as to the adaptive value of filial cannibalism in [[teleost]]s is that it increases density-dependent egg survivorship. In other words, filial cannibalism simply increases overall reproductive success by helping the other eggs make it to maturity by thinning out the numbers. Possible explanations as to why this is so include increasing oxygen availability to the remaining eggs,<ref>Payne, A. G., C. Smith, and A. C. Campbell. 2002. Filial cannibalism improves survival and development of beaugregory damselfish embryos. Proceedings of the Royal Society of London Series B-Biological Sciences 269:2095-2102.</ref> the negative effects of accumulating embryo waste,<ref name="Klug, H. 2006">Klug, H., K. Lindstrom, and C. M. S. Mary. 2006. Parents benefit from eating offspring: density-dependent egg survivorship compensates for filial cannibalism. Evolution 60:2087-2095.</ref> and predation.<ref name="Klug, H. 2006"/> ▼
▲AnotherOutra hypothesishipótese assobre too thevalor adaptiveadaptativo valuedo ofcanibalismo filial cannibalismen inteleósteos [[teleost]]sé isque thatincrementa ita increasessupervivencia density-dependentdos eggovos dependente de survivorshipdensidade. InNoutras other wordspalabras, o canibalismo filial cannibalismsimplemente simplyincrementa increaseso overalléxito reproductivereprodutivo successglobal byao helpingaxudar theque otheros eggsoutros makeovos itque toquedan maturitycheguen byá thinningmadurez outao thediminuír a súa numberscantidade. PossiblePosibles explanationsexplicacións asdisto toson whyo thisincremento isda sodispoñibilidade includede increasingoxíxeno oxygenpara availabilityo toresto the remainingdos eggsovos,<ref>Payne, A. G., C. Smith, and A. C. Campbell. 2002. Filial cannibalism improves survival and development of beaugregory damselfish embryos. Proceedings of the Royal Society of London Series B-Biological Sciences 269:2095-2102.</ref> theos negativeefectos effectsnegativos ofda accumulatingacumulación embryode wasteresiduos dos embrións,<ref name="Klug, H. 2006">Klug, H., K. Lindstrom, and C. M. S. Mary. 2006. Parents benefit from eating offspring: density-dependent egg survivorship compensates for filial cannibalism. Evolution 60:2087-2095.</ref> ande a predationpredación.<ref name="Klug, H. 2006"/>
In some species of eusocial wasps, such as ''[[Polistes chinensis|P. chinensis]]'', the reproducing female will kill and feed younger larvae to her older brood. This occurs under food stressed conditions in order to ensure that the first generation of workers emerges without delay. <ref>Kudo, K.; Shirai, A. (5 January 2012). "Effect of food availability on larval cannibalism by foundresses of the paper wasp Polistes chinensis antennalis". Insect Soc. 59: 279–284.</ref> ▼Further evidence also suggests that occasionally filial cannibalism might be the unfortunate by-product of [[cuckoldry in fish]]. Males consume broods, which may include their own offspring, when they believe a certain percentage of the brood contains genetic material that is not theirs.<ref name="Mehlis, M. 2010"/><ref>Gray, S. M., L. M. Dill, and J. S. McKinnon. 2007. Cuckoldry incites cannibalism: male fish turn to cannibalism when perceived certainty of paternity decreases. American Naturalist 169:258-263.</ref> ▼
▲InNalgunhas someespecies speciesde of eusocial[[avespa]]s waspseusociais, such ascomo ''[[Polistes chinensis|P. chinensis]]'', thea reproducingfemia femalereprodutora willmata kille anddá feedde youngercomer larvaeas tolarvas hermáis oldernovas brood.ás Thissúas crías máis vellas. occursIsto underocorre foodcando stressedhai conditionsescaseza inde ordercomida topara ensuresegurarse thatque thea firstprimeira generationxeración ofde workersobreiras emergesemerxa withoutsen delayretraso. <ref>Kudo, K.; Shirai, A. (5 January 2012). "Effect of food availability on larval cannibalism by foundresses of the paper wasp Polistes chinensis antennalis". Insect Soc. 59: 279–284.</ref>
The [[dinosaur]] ''[[Coelophysis]]'' was once suspected to practice this form of cannibalism but this turned out to be wrong, although ''[[Deinonychus]]'' may have done. Skeletal remains from subadults with missing parts are suspected of having been eaten by other ''Deinonychus'', mainly full-grown adults.
▲FurtherOutras evidenceevidencias alsosuxiren suggestsque thatocasionalmente occasionallyo canibalismo filial cannibalismpodería mightser beo thesubproduto unfortunateinfortunado by-product ofda [[cuckoldry in fish]]. MalesOs consumemachos broodsconsomen niñadas, whichque maypoden includeincluír theira ownsúa offspringpropia descendencia, whencando theycren believeque aunha certaincerta percentageporcentaxe ofda theniñada broodcontén containsmaterial geneticxenético materialque thatnon isé noto theirsseu.<ref name="Mehlis, M. 2010"/><ref>Gray, S. M., L. M. Dill, and J. S. McKinnon. 2007. Cuckoldry incites cannibalism: male fish turn to cannibalism when perceived certainty of paternity decreases. American Naturalist 169:258-263.</ref>
Antes sospeitábase que os [[dinosauro]]s ''[[Coelophysis]]'' practicaban esta forma de canibalismo, pero isto considérase agora incorrecto, aínda que ''[[Deinonychus]]'' pode que si o fixese. Os restos esqueléticos de subadultos con partes desaparecidas sospéitase que foron comidos por outros ''Deinonychus'' adultos.
=== Infanticide ===
{{main|Infanticide (zoology)}}
=== Infanticidio ===
Infanticide is the killing of a non-adult animal by an adult of the same species. Infanticide is often, but not always, accompanied by cannibalism. It is often displayed in [[lions]]; a male lion encroaching on the territory of a rival pride will often kill any existing cubs fathered by other males; this brings the lionesses into heat more quickly, enabling the invading lion to sire his own young. This is a good example of cannibalistic behavior in a genetic context.
== IntrauterineCanibalismo cannibalismintrauterino ==
[[Sibling rivalry (animals)#Intrauterine cannibalism|Intrauterine cannibalism]] is a behaviour in some carnivorous species, in which multiple embryos are created at impregnation, but only one or two are born. The larger or stronger ones consume their less-developed siblings as a source of nutrients.
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