Altruism in animals
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'''[[Altruism]]''' is a well-documented [[animal behaviour]], which appears most obviously in kin relationships but may also be evident amongst wider social groups.
== Overview ==
:{{See also|Ethics and evolutionary psychology}}
In the science of [[ethology]] (the study of behavior), and more generally in the study of [[social evolution]], [[altruism]] refers to behavior by an individual that increases the [[fitness (biology)|fitness]] of another individual while decreasing the fitness of the actor.<ref>{{Cite journal
| author = [[Robert L. Trivers]]
| title = The Evolution of Reciprocal Altruism
| journal = [[The Quarterly Review of Biology]]
| volume = 46
| issue = 1
| year = 1971
| pages = 35
| doi = 10.1086/406755
}}</ref>. Research in [[evolutionary theory]] has been applied to social behaviour, including altruism. Some animal altruistic behaviour is explained by [[kin selection]]. Beyond the physical exertions that mothers, and in some species fathers, undertake to protect their young, extreme examples of sacrifice may occur. One example is [[matriphagy]] (the consumption of the mother by her offspring) in the spider ''[[Stegodyphus]]''. [[Hamilton's rule]] describes the benefit of such altruism in terms of [[Sewall Wright|Wright's]] [[coefficient of relationship]] to the beneficiary and the benefit granted to the beneficiary minus the cost to the sacrificer. Should this sum be greater than zero a fitness gain will result from the sacrifice.
When apparent altruism is not between kin, it may be based on [[reciprocal altruism|reciprocity]]. A monkey will present its back to another monkey, who will pick out parasites; after a time the roles will be reversed. Such reciprocity will pay off, in evolutionary terms, as long as the costs of helping are less than the benefits of being helped and as long as animals will not gain in the long run by "cheating" - that is to say, by receiving favours without returning them. This is elaborated on in [[evolutionary game theory]] and specifically the [[prisoner's dilemma]] as social theory.
==Implications in evolutionary theory==
Researchers on alleged altruist behaviours among animals have been ideologically opposed to the [[social darwinism|social darwinist]] concept of the "[[survival of the fittest]]", under the name of "survival of the nicest" — the latter being globally compatible, however, with [[darwinism|darwinist]]' [[theory of evolution]]. Insistence on such cooperative behaviours between animals was first exposed by the Russian zoologist and anarchist [[Peter Kropotkin]] in his 1902 book, ''[[Mutual Aid: A Factor of Evolution]]''.
Recent developments in [[game theory]] (look into [[ultimatum game]]) have provided some explanations for apparent altruism, as have traditional evolutionary analyses. Among the proposed mechanisms are:
* Behavioural manipulation (for example, by certain [[parasites]] that can alter the behavior of the host)
* [[Bounded rationality]] (for example, [[Herbert Simon]])
* [[Conscience]]
* [[Kin selection]] including [[eusociality]] (see also "[[The Selfish Gene]]")
* [[Meme]]s (by influencing behavior to favour their own spread, for example, [[religion]])
* [[Reciprocal altruism]], mutual aid
* [[Sexual selection]], in particular, the [[Handicap principle]]
* [[Reciprocity (social psychology)]]
** Indirect reciprocity (for example, [[reputation]])
** Strong reciprocity<ref>{{Cite journal
| author = Herbert Gintis
| title = Strong Reciprocity and Human Sociality
| journal = [[Journal of Theoretical Biology]]
| volume = 206
| issue = 2
| month = September
| year = 2000
| pages = 169–179
| doi = 10.1006/jtbi.2000.2111
}}</ref>
* Pseudo-reciprocity
The study of altruism was the initial impetus behind [[George R. Price]]'s development of the [[Price equation]] which is a mathematical equation used to study genetic evolution. An interesting example of altruism is found in the cellular [[slime mould]]s, such as ''[[Dictyostelid|Dictyostelium]] mucoroides''. These protists live as individual [[amoebae]] until starved, at which point they aggregate and form a multicellular fruiting body in which some cells sacrifice themselves to promote the survival of other cells in the fruiting body. Social behavior and altruism share many similarities to the interactions between the many parts (cells, genes) of an organism, but are distinguished by the ability of each individual to reproduce indefinitely without an absolute requirement for its neighbors.
Jorge Moll and Jordan Grafman, neuroscientists at the [[National Institutes of Health]] and LABS-D'Or Hospital Network (J.M.) provided the first evidence for the neural bases of altruistic giving in normal healthy volunteers, using [[functional magnetic resonance imaging]]. In their research, published in the [[Proceedings of the National Academy of Sciences]] USA in October, 2006,<ref>Human fronto–mesolimbic networks guide decisions about charitable donation, PNAS 2006:103(42);15623-15628)</ref> they showed that both pure monetary rewards and charitable donations activated the [[Mesolimbic pathway|mesolimbic]] reward pathway, a primitive part of the brain that usually lights up in response to food and sex. However, when volunteers generously placed their interests of others before their own by making charitable donations, another brain circuit was selectively activated: the subgenual cortex/septal region. These structures are intimately related to social attachment and bonding in other species. Altruism, the experiment suggested, was not a superior moral faculty that suppresses basic selfish urges but rather was basic to the brain, hard-wired and pleasurable.<ref name="brain">{{cite news
|url=http://www.washingtonpost.com/wp-dyn/content/article/2007/05/27/AR2007052701056.html
|title=If It Feels Good to Be Good, It Might Be Only Natural
|publisher=Washington Post
|date=May 2007
}}</ref>
A new study by [[Samuel Bowles (economist)|Samuel Bowles]] at the [[Santa Fe Institute]] in [[New Mexico]], US, is seen by some as breathing new life into the model of [[group selection]] for Altruism, known as "Survival of the nicest". Bowles conducted a genetic analysis of contemporary foraging groups, including [[Australian aboriginals]], native [[Siberian]] [[Inuit]] populations and indigenous tribal groups in Africa. It was found that [[hunter-gatherer]] bands of up to 30 individuals were considerably more closely related than was previously thought. Under these conditions, thought to be similar to those of the middle and upper [[Paleolithic]], altruism towards other group-members would improve the overall fitness of the group.
If an individual defended the group but was killed, any genes that the individual shared with the overall group would still be passed on. Early customs such as food sharing or [[monogamy]] could have levelled out the “cost” of altruistic behaviour, in the same way that income taxes redistribute income in society. He assembled genetic, climactic, archaeological, ethnographic and experimental data to examine the cost-benefit relationship of human cooperation in ancient populations. In his model, members of a group bearing genes for altruistic behaviour pay a "tax" by limiting their reproductive opportunities to benefit from sharing food and information, thereby increasing the average fitness of the group as well as their inter-relatedness. Bands of altruistic humans would then act together to gain resources from other groups at this challenging time in history.<ref>Fisher, Richard (07 December 2006) "Why altruism paid off for our ancestors" (NewScientist.com news service) [http://www.newscientist.com/article/dn10750.html]</ref>.
Altruist theories in evolutionary biology were contested by [[Amotz Zahavi]], the inventor of the signal theory and its correlative, the [[handicap principle]], based mainly on his observations of the [[Arabian Babbler]], a bird commonly known for its surprising (alleged) altruistic behaviours.
== Examples of animal altruism ==
*[[Dogs]] often adopt orphaned [[cats]], [[squirrels]], [[ducks]] and even [[tigers]].<ref>[http://dogsinthenews.com/stories/060929a.php Mutt-ernal Instincts - Dachshund adopts kitties, Pitbull adopts kitties, Border Collie adopts... tigers? - 2006-09-29<!-- Bot generated title -->]</ref>
*[[Dolphin]]s support sick or injured animals, swimming under them for hours at a time and pushing them to the surface so they can breathe.{{fact|date=May 2008}}
*[[Wolf|Wolves]] and [[Dog|wild dogs]] bring meat back to members of the pack not present at the kill.{{Fact|date=January 2008}}
*Male [[baboon]]s threaten predators and cover the rear as the troop retreats. {{Fact|date=January 2008}}
*[[Gibbon]]s and [[chimpanzee]]s with food will, in response to a gesture, share their food with others of the group. {{Fact|date=January 2008}}. Chimpanzees will help other humans and [[Conspecificity|Conspecifics]] without any reward in return<ref>[http://www.sciencedaily.com/releases/2007/06/070625085134.htm Human-like Altruism Shown In Chimpanzees<!-- Bot generated title -->]</ref>
*[[Bonobo]]s have been observed aiding injured or handicapped bonobos.<ref>[http://www.sciencefriday.com/pages/2005/Oct/hour2_100705.html October 7, 2005, Hour Two:<!-- Bot generated title -->]</ref>
*According to the research of Gerald Wilkinson, [[vampire bat]]s have a "[[buddy system]]" in which a bat who has had a successful night of feeding will regurgitate blood for its less fortunate companion.<ref>{{cite book |last=de Waal |first=Frans |authorlink=Frans de Waal |title=Good Natured |year=1996 |publisher=[[Harvard University Press]] |pages=20–21 |id=ISBN 0-674-35660-8 }}</ref>
*In numerous bird species, a breeding pair receives support in raising its young from other "helper" birds, including help with the feeding of its fledglings.<ref>[http://www.washingtonpost.com/wp-dyn/content/article/2007/08/16/AR2007081602257.html Birds' Cooperative Breeding Sheds Light on Altruism - washingtonpost.com<!-- Bot generated title -->]</ref> Some will even go as far as protecting an unrelated bird's young from predators <ref>[http://findarticles.com/p/articles/mi_m1200/is_n23_v135/ai_7680117 Avian altruism: African birds sacrifice self-interest to help their kin - white-fronted bee eaters | Science News | Find Articles at BNET.com<!-- Bot generated title -->]</ref>
*Most mammal carnivores like wolves or dogs have a habit of not harming pack members below certain age, of opposite sex or in surrendering position (in case of some animals, the behavior exists within entire species rather than one pack).{{Fact|date=January 2008}}
*[[Vervet Monkey]]s give alarm calls to warn fellow monkeys of the presence of predators, even though in doing so they attract attention to themselves, increasing their personal chance of being attacked.<ref>{{cite book | author=Cheney, D. L. & Seyfarth, R. M. | year=1990 | url=http://books.google.co.uk/books?id=QbWTd85eHUgC | title=How monkeys see the world: Inside the mind of another species | publisher=University of Chicago Press}}</ref>
*[[Walrus]]es have been seen adopting orphans who lost their parents to predators.{{Fact|date=January 2008}}
*[[Termite]]s release a sticky secretion by rupturing a gland near the skin in their neck, this autothysis defends against invading ants by creating a [[tar baby]] effect.<ref>{{cite journal |author=Bordereau, C., Robert, A., Van Tuyen V. & A. Peppuy |year=1997 |title=Suicidal defensive behavior by frontal gland dehiscence in ''Globitermes sulphureus'' Haviland soldiers (Isoptera) |journal=Insectes Sociaux |volume=44 |issue=3 |pages=289–297 |doi=10.1007/s000400050049}}</ref>
== See also ==
* [[Evolutionarily stable strategy]]
* [[Gene-centered view of evolution]]
* [[Sociobiology]]
==References==
{{reflist}}
== External links ==
* [http://plato.stanford.edu/entries/altruism-biological/ Biological Altruism ]
* [http://www.iussi.org/ International Union for the Study of Social Insects]
* [http://www.ruf.rice.edu/%7Eevolve/pdf/20002001/CurBio2002_12_R832.pdf Quick Guide: Kin Selection (Current Biology)]
* [http://westgroup.icapb.ed.ac.uk/pdf/West_etal_06_altruism.pdf Quick Gude: Altruism (Current Biology)]
* [http://dogsinthenews.com/stories/060929a.php "Mutt-ernal Instincts"] An article about dogs caring for other species' young (cats, tigers, etc).
[[Category:Behavioral ecology]]
[[Category:Ethology]]
[[Category:Evolution by phenotype]]
[[Category:Social psychology]]