Editing Animal sexual behaviour (section)

==Types of activity==
===Autoeroticism (masturbation)===
<!-- Unsourced image removed: [[Image:Dog and toy.png|thumb|210px|[[Dog]] (canis familiaris) masturbating against a [[stuffed toy]]. (Source: movie still)]] -->
It appears that many animals, both male and female, masturbate, both when partners are available and otherwise.

For example, http://www.petplace.com comments in its guide on assessing potential breeding stock purchases: ''"Masturbation is a normal behaviour in all stallions that does not reduce semen production or performance in the breeding shed, and thus the use of devices to prevent such behaviour is strongly discouraged and can be harmful to the stallion."''<ref>[http://www.petplace.com/horses/breeding-soundness-examination-of-the-stallion/page2.aspx Breeding Soundness Examination of the Stallion]</ref> Likewise the paper "Sexual Behaviour - Current Topics in Applied Ethology and Clinical Methods" by Sue McDonnell of the Equine Behaviour Laboratory, University of Pennsylvania School of Veterinary Medicine states:

{{quote|One example is the behaviour known within the horse breeding industry as masturbation. This involves normal periodic erections and penile movements. This behaviour, both from the descriptive field studies cited above and in extensive study of domestic horses, is now understood as normal, frequent behaviour of male equids.|<ref name="McDonnell,Henry,Bristol,1991">McDonnell, S.M., Henry, M., & Bristol, F. (1991). Spontaneous erection and masturbation in equids. Proceedings Vth International Equine Reproduction Symposium. J Reprod Fert Suppl, 44, 664-665.</ref>}}

Attempting to inhibit or punish masturbation, for example by tying a brush to the area of the flank underside where the penis rubs into contact with the underside, which is still a common practice of horse managers regionally around the world, often leads to increased masturbation and disturbances of normal breeding behaviour (McDonnell and Hinze, in preparation).<ref>[http://www3.vet.upenn.edu/labs/equinebehaviour/hvnwkshp/hv02/mcdonnell.htm Sexual Behaviour - Current Topics in Applied Ethology and Clinical Methods]</ref>. Castration does not prevent masturbation, as it is also observed in geldings, and even mares.

<!-- Image with disputed fair-use status removed:  [[Image:M90.org kangeroo film still.png|thumb|240px|Still from TV show, accidentally capturing animal masturbation by a [[kangaroo]]]] -->
Sexual release seeking is common in both domestic and non-domestic species. For example, a video (non-explicit) showing a kangaroo masturbating, inadvertently caught during a TV broadcast, can be found [http://www.youtube.com/watch?v=DoKrMW8giGg here]. Also, another video (explicit) of a kangaroo performing [[autofellatio]] can be found [http://www.youtube.com/watch?v=vGPLrRqkDY8&NR here], and a dog balancing on rear legs in order to masturbate with both front paws, [http://www.youtube.com/watch?v=0ZCoeZn09ws here].

The female [[porcupine]] has been observed to use a stick as a [[Vibrator (sensual)|vibrator]], holding one end of a stick and walking around, straddling it as it bumped against the ground and vibrated against her genitalia.<ref>[http://influx.uoregon.edu/1997/wham/ Don't Hold Back]</ref> Sexologist [[Havelock Ellis]] in his 1927 "Studies in the Psychology of Sex" identified bulls, goats, sheep, camels and elephants as species known to practice autoeroticism, adding of some other species: 

{{quote|I am informed by a gentleman who is a recognized authority on goats, that they sometimes take the penis into the mouth and produce actual orgasm, thus practicing auto-fellatio. As regards ferrets ... "if the bitch, when in heat, cannot obtain a dog [ie, male ferret] she pines and becomes ill. If a smooth pebble is introduced into the hutch, she will masturbate upon it, thus preserving her normal health for one season. But if this artificial substitute is given to her a second season, she will not, as formerly, be content with it." [...] Blumenbach observed a bear act somewhat similarly on seeing other bears coupling, and hyenas, according to Ploss and Bartels, have been seen practicing mutual masturbation by licking each other's genitals.}}

<!-- Unsourced image removed: [[Image:Cow and tractor.png|thumb|240px|Inanimate farm equipment such as [[tractor]]s or [[hay]], is sometimes employed as a [[tool]] for animal masturbation]] -->
In his 1999 book, ''Biological exuberance'',  Bruce Bagemihl PhD documents (p.71, 209-210) that:

{{quote|Autoeroticism also occurs widely among animals, both male and female. A variety of creative techniques are used, including genital stimulation using the hand or front paw (primates, Lions), foot (Vampire Bats, primates), flipper (Walruses), or tail (Savanna Baboons), sometimes accompanied by stimulation of the nipples (Rhesus Macaques, Bonobos); auto-fellating or licking, sucking and/or nuzzling by a male of his own penis (Common Chimpanzees, Savanna Bonobos, Vervet Monkeys, Squirrel Monkeys, Thinhorn Sheep, Bharal, Aovdad, Dwarf Cavies); stimulation of the penis by flipping or rubbing it against the belly or in its own sheath (White-tailed and Mule Deer, Zebras and Takhi); spontaneous ejaculations (Mountain Sheep, Warthogs, Spotted Hyenas); and stimulation of the genitals using inanimate objects (found in several primates and cetaceans).|<ref name="Bagemihl,1999">Bruce Bagemihl: Biological Exuberance: Animal Homosexuality and Natural Diversity. St. Martin's Press, 1999. ISBN 0-312-19239-8</ref>}}

{{quote|Many birds masturbate by mounting and copulating with tufts of grass, leaves or mounds of earth, and some mammals such as primates and Dolphins also rub their genitals against the ground or other surfaces to stimulate themselves.|<ref name="Bagemihl,1999" />}}

{{quote|Autoeroticism in female mammals, as well as heterosexual and homosexual intercourse (especially in primates), often involves direct or indirect stimulation of the clitoris [...]. This organ is present in the females of all mammalian species and several other animal groups.|<ref name="Bagemihl,1999" />}}

and that:

{{quote|Apes and Monkeys use a variety of objects to masturbate with and even deliberately create implements for sexual stimulation [...] often in highly creative ways.|<ref name="Bagemihl,1999" />}}

Petter Bøckman of the Norwegian Natural History Museum commented (in respect of a 2006 [[Against Nature?|exhibition on homosexuality in the animal kingdom]]) that:

{{quote|Masturbation is common in the animal kingdom ... We have a [[Darwinism|Darwinist]] mentality that all animals only have sex to procreate. But there are plenty of animals who will masturbate when they have nothing better to do. Masturbation has been observed among primates, deer, killer whales and penguins, and we're talking about both males and females. They rub themselves against stones and roots. Orangutans are especially inventive. They make [[dildo]]s of wood and bark.|<ref name="news-medical" />}}

===Oral sex===
Animals of several species are documented as engaging in both [[autofellatio]] and [[oral sex]]. Although easily confused by lay-people, this is a separate and sexually oriented behaviour, distinct from non-sexual [[social grooming|grooming]] or the investigation of scents.

Auto-fellatio or oral sex in animals is documented in [[goat]]s, [[primate]]s, [[hyaena]]s and [[sheep]]. (see section [[#Autoeroticism (masturbation)|Masturbation]] for details).

===Homosexual behaviour===
{{Main|Homosexuality in animals}}
[[Image:Males Anas platyrhynchos 2 .jpg|thumb|Male [[Mallard]]s, ''Anas platyrhynchos''.]]
The presence of [[same-sex sexual behaviour]] was not scientifically observed on a large scale until recent times. Homosexual behaviour does occur in the [[animal]] kingdom outside humans, especially in social species, particularly in marine birds and mammals, monkeys, and the [[Hominidae|great apes]]. Homosexual behaviour has been observed among 1,500 species, and in 500 of those it is well documented.<ref>{{cite web |url=http://news.bbc.co.uk/2/hi/europe/6066606.stm |title=Oslo gay animal show draws crowds |accessdate=2006-10-19 |date=2006-10-19|work=BBC News}}</ref> 

{{quote|To turn the approach on its head: No species has been found in which homosexual behaviour has not been shown to exist, with the exception of species that never have sex at all, such as sea urchins and aphis. Moreover, a part of the animal kingdom is hermaphroditic, truly bisexual. For them, homosexuality is not an issue.|<ref name="news-medical" />}}

[[Georgetown University]] professor [[Janet Mann]] has specifically theorised that homosexual behaviour, at least in [[dolphin]]s, is an evolutionary advantage that minimizes intraspecies aggression, especially among males.
*Male [[penguin]] couples have been documented to mate for life, build nests together, and to use a stone as a [[surrogate]] egg in nesting and brooding. In 2004, the [[Central Park Zoo]] in the [[United States]] replaced one male couple's stone with a fertilized egg, which the couple then raised as their own offspring.<ref>[http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2004/02/07/MNG3N4RAV41.DTL "Central Park Zoo's gay penguins ignite debate"] by Dinitia Smith, ''San Francisco Chronicle'', February 7, 2004</ref> [[Germany|German]] and [[Japan]]ese [[zoo]]s have also reported homosexual behaviour among their penguins. This phenomenon has also been reported at Kelly Tarlton's Aquarium in [[Auckland]], [[New Zealand]].  "Humans have created the myth that sexuality can be justified only by reproduction, which by definition limits it to hetero sex," says Michael Bronski, author of The Pleasure Principle: Culture, Backlash, and the Struggle for Gay Freedom. "But here is an animal society that uses homosexuality to improve its social life."
*Mounting of one female by another is common among [[cattle]]. (''See also, [[Freemartin]]. Freemartins occur because of clearly causal hormonal factors at work during gestation''.)
*[[Bonobo]]s in zoos. After studying the primates for his book ''Bonobo: The Forgotten Ape'', primatologist [[Frans de Waal]], a professor of psychology at Emory University in Atlanta, says that such expressions of [[intimacy]] are consistent with the homosexual behaviour of what he terms "the erotic champions of the world." "Same-sex, opposite-sex — bonobos just [[love]] sex play," de Waal said in an interview. "They have so much sex, it gets boring."
*Homosexual behaviour in male sheep (found in 6-10% of rams) is associated with variations in cerebral mass distribution and chemical activity. A study reported in ''[[Endocrinology (journal)|Endocrinology]]'' concluded that biological and physiological factors are in effect.<ref>[http://endo.endojournals.org/cgi/content/abstract/145/2/478 "The Volume of a Sexually Dimorphic Nucleus in the Ovine Medial Preoptic Area/Anterior Hypothalamus Varies with Sexual Partner Preference"] by Charles E. Roselli, et al., The Endocrine Society, October 2, 2003</ref> These findings are similar to human findings reported by [[Simon LeVay]].

:<blockquote>Approximately eight percent of [male] rams exhibit sexual preferences [that is, even when given a choice] for male partners (male-oriented rams) in contrast to most rams, which prefer female partners (female-oriented rams). We identified a cell group within the medial preoptic area/anterior hypothalamus of age-matched adult sheep that was significantly larger in adult rams than in ewes...</blockquote>
*Male bighorn sheep are divisible into two kinds: the typical males among whom homosexual behaviour, including intercourse, is common and "effeminate sheep", or "behavioural transvestites", which are not known to engage in homosexual behaviour.<ref>[http://www.washingtonpost.com/ac2/wp-dyn/A22107-2004Jul1?language=printer In BriefRams Will Be Rams]</ref><ref>[http://www.stanfordalumni.org/news/magazine/2004/mayjun/features/roughgarden.html On the Originality of Species]</ref>

===Cross species sex===

<!-- Unsourced image removed: [[Image:Racoon and dog.png|thumb|210px|A [[raccoon]] attempting [[coitus]] with a [[dog]]. Photographs of cross species sex involving wild species are rare, since many species do not share their territory with competitor species, or are hard to observe.]] -->
While it is commonly believed that animal sexuality is instinctive and thus somewhat mechanistic, research regularly records that many animals are sexual opportunists, partaking in sexual relations with individuals of visibly distinct species <ref>http://news.bbc.co.uk/2/hi/science/nature/7379554.stm "The seal then alternated between resting on the penguin, and thrusting its pelvis, trying to insert itself, unsuccessfully."</ref>.  This is more visible in domesticated species and animals in captivity, as domestication commonly selects for increased breeding rate (and so an accelerated breeding cycle has commonly arisen in domesticated species over the centuries), and also because these species are more easily observed by humans. Nevertheless, animals have been observed in the wild to attempt sexual activity with other species or indeed inanimate objects.  Attempts by wild [[moose]] to obtain sex from domestic [[horse]]s are apparently well known by wildlife specialists.{{Fact|date=November 2008}} 

In the wild, where observation is harder, genetic studies have shown a "large number" of inter-species hybrids, and other investigations describe productive and non-productive inter-species mating as a "natural occurrence".<ref>Haeberle (1978) states that sexual intercourse is not so very unusual between animals of different species as it is between humans and animals. Kinsey et al. (1948, p. 668) states "When one examines the observed cases of such crosses, and especially the rather considerable number of instances in which primates, including man, have been involved, one begins to suspect that the rules about intraspecific mating are not so universal as tradition would have it". Kinsey et al. (1953) [[further]] point out that genetic studies have shown the existence of a "large number" of inter-specific hybrids, that have occurred in the wild, and investigations (eg, Cauldwell, 1968; Ford & Beach, 1951; Harris, 1969; Masters, 1962; Ullerstam, 1966, etc) have found that [[interspecies]] mating is a "natural occurrence".' (Cited by [[Hani Miletski|Miletski]], in her [[anthrozoology|anthrozoological]] study of animal-human sexuality, 1999, p.51)</ref> Recent genetic evidence strongly suggesting this has occurred even within the history of the [[human]] species, and that early humans often had sexual activity with other primate species, is [[#Other evidence of interspecies sexual activity|considered below]].

[[Hybrid (biology)|Hybrid]] offspring can result from two organisms of distinct but closely related parent species, although the resulting offspring is not always [[fertile]] {{Fact|date=April 2008}}. According to the definition of a species, If two organisms ''cannot or will not'' mate and produce a fertile offspring, they are different species {{Fact|date=April 2008}}. The [[mule]], for example (a horse/donkey cross) is normally sterile, whilst the [[liger]] (lion/tiger cross) has fertile females and sterile males. Novosibirsk zoo director Rostislav Shilo says on the liger (born in its zoo); "It’s just that the lion and the tiger live in neighboring caves in the Novosibirsk zoo, and got used to each other. It’s practically impossible in the wild" {{Fact|date=April 2008}}.

Due to the difficulties of observation, interspecies sex of this kind between two top-level predators, occurring in the wild, was only conclusively documented with the finding of a [[grizzly-polar bear hybrid]] in [[April 2006]]<ref name="msn">{{cite news  |url = http://msnbc.msn.com/id/12738644/?GT1=8199 |title = Wild find: Half grizzly, half polar bear: Hunter bags what expert 'never thought would happen' in wild |publisher = MSNBC.MSN.com |date = [[May 11]], [[2006]] |accessdate = 2006-05-14}}</ref>. Again, as with lions and tigers, the two species would normally not share enough common territory to provide adequate opportunity for much cross-species sexual activity{{Fact|date=April 2008}}. In other words, whether both species were 0% or 100% promiscuous and sought sex with the same species only or the nearest bear of any species, the overwhelming number of matings would still of necessity be with the same species.

Animal sexual advances on, and attempted interactions with, humans and other species, have been documented by [[Ethology|ethologists]] such as [[Kohler]], [[Gerald Durrell]] and [[Desmond Morris]], as well as authoritative researchers such as [[Birute Galdikas]] who studied [[orangutan]]s in [[Borneo]]. Philosopher and [[animal welfare]] activist [[Peter Singer]] reports:

{{quote|While walking through the camp with Galdikas, my informant was suddenly seized by a large male orangutan, his intentions made obvious by his erect penis.  Fighting off so powerful an animal was not an option, but Galdikas called to her companion not to be concerned, because the orangutan would not harm her, and adding, as further reassurance, that 'they have a very small penis' ... though the orangutan lost interest before penetration took place.<ref>[http://www.utilitarian.net/singer/by/2001----.htm Heavy Petting]</ref>}}

===Prostitution===

In some [[penguin]] species, the females, even when in a committed relationship, will exchange sexual favours  with strange males for the [[pebble]]s they need to build their [[nest]]s.<ref>{{cite news  | title = Penguins are turning to prostitution.  | publisher = BBC  | date = [[1998-02-26]]  | url = http://news.bbc.co.uk/2/hi/asia-pacific/60302.stm  | accessdate = 2008-06-12}}</ref>

===Sexual fetishes===
{{See also|operant conditioning}}
Although not often reported, it appears{{weasel-inline}} animals, or primates at the least, are able to sexualize inanimate objects similar to the way human beings sexualize the objects of their [[sexual fetish]]es. Not only will an animal that has a habitual object for masturbation sometimes appear to sexualize that object, primates have generalized further to sexualize ''kinds of objects'' for which no instinctual or prior sexual connection exists. {{Fact|date=April 2008}}

Thus Gabriel, a chimpanzee at the [[Southwest National Primate Research Center]], is said to have a shoe fetish (or possibly a leather fetish) according to caretaker Bert Barrera, and it is reported that:

{{quote|A male chimpanzee raised in captivity developed a bit of a shoe fetish, masturbating obsessively by rubbing his caretaker's leather boot.|[http://www.mysanantonio.com/news/metro/stories/MYSA101904.01B.Chimp_homes.7bca96.html mysanantonio.com]}}

The sexualization of objects or locations is also well recognized in the breeding world. So for example, [[stallion (horse)|stallion]]s may often 'drop' (become [[sexual arousal|sexually aroused]]) upon visiting a location where they have been allowed to have sex before, or upon seeing a stimulus previously associated with sexual activity such as an [[artificial vagina]]. {{Fact|date=February 2007}}

In this case however, the primary structure is [[Pavlovian conditioning]], and the fetishistic association is due to a conditioned response (or association) formed with a distinctive '[[reward]]'. Human fetishism can also be traced back to similar or near-identical conditioning: likewise based upon the Pavlovian association between an erotic sensation or [[pelvic congestion|anticipation]], and objects which become mentally associated with that activity. {{Fact|date=February 2007}}

===Sexual imagery viewing===
A study by Platt, Khera and Deaner at Duke University North Carolina (reported in ''[[Current Biology]]'' and online [http://www.bioedonline.org/news/news.cfm?art=1551 here]), showed that male monkeys will give up privileges (in this case, juice, which was highly valued), to be allowed to see a female monkey's hindquarters.<ref name="Deaner,Khera,Platt,2005">[http://www.current-biology.com/content/article/abstract?uid=PIIS0960982205001041 Current Biology - Deaner M. O., Khera A. V. & Platt M. L. Curr. Biol. published online]</ref> 

Deaner and his team reported that monkeys would take a juice cut to look at powerful males' faces or the perineum of a female, but to persuade the monkeys to stare at subordinate males, the researchers had to bribe them with larger drinks. "Virtually all [male] monkeys will give up juice to see female hindquarters ... they really value the images." 

The researchers stress that in monkey society, such behaviours have great social utility and we should therefore not simply reach the conclusion that "monkeys enjoy pornographic pictures". There is no evidence at this point that viewable pictures or movies of sexual activity are valued for their sexual enjoyment, although as noted above ([[#Autoeroticism (masturbation)|Masturbation]]), there are reports that watching sex in real life may have such an effect. The subject of animals and sexual imagery is not yet well researched.

Problems with encouraging [[panda]]s to mate in captivity have been very common. However, showing young male pandas "panda pornography" is widely credited with a recent population boom among pandas in zoos.<ref>[http://www.msnbc.msn.com/id/15852885/ ''Porn sparks panda baby boom in China: Research — and blue movies — attributed to record-high birth rate in 2006'', Denis D. Gray, Associated Press, 4:58 p.m. ET Nov 27, 2006]</ref>

===Coercive sex===
Controversial interpretations and implications aside (see [[Sociobiological theories of rape]]), sex in a forceful or apparently coercive context has also been documented in a variety of species. A notable example is [[bottlenose dolphin]]s, where at times, gangs of [[bachelor herd|bachelor]] males 'corner' females.<ref>N. Angier, ''New York Times'' 18th February 1992, 'Dolphin courtship: brutal, cunning and complex' </ref> Furthermore, in a zoo where it is common practice to put newly captured dolphins in with dolphins who are established in their enclosures, other species of dolphin are never put in together with bottlenoses because they frequently torment and rape them.<ref>M. Ventura, 'The zoo where you're fed to God', ''L.A. Weekly'' 11-17 December 19992, p. 18</ref>
The behaviour is also common in some [[arachnid]]s (spiders), notably those whose females eat the males during sex if not tricked with food and/or tied down with threads,<ref>Making Love Can Be real Sacrifice: http://www.smh.com.au/articles/2003/08/10/1060454080025.html?from=storyrhs, retrieved Nov 6 2007</ref> and in some [[herbivore|herbivorous]] herd species or species where males and females are very different in size, where the male dominates sexually by sheer force and size.{{Fact|date=November 2007}} 

Some species of birds appear to combine sexual intercourse with apparent violent assault; these include [[duck]]s,<ref>R.O.Bailey, N. R. Seymour and G.R. Stewart, 'Rape behaviour in blue-winged teal', ''Auk'' 95 (1978), pp. 188-90.  Also D.P. Barash, 'Sociobiology of rape in mallards  (Anas platyrhynchos): responses of the [[mated]] male;, ''Science''197(19 August 1977) pp. 788-9''</ref> [[geese]], and [[white-fronted bee-eater]]s.  According to Emlen and Wrege (1986)<ref>S.T. Emlen and P.H. Wrege 'Forced copulations and intraspecific parasitism: two costs of social living in the white-fronted bee-eater' ''Ethology'' 71 (1986) pp.2-29</ref> forced copulations occur in this socially nesting species, and females must avoid the unwelcome attention of males as they emerge from their nest burrows or they are forced to the ground and mated with.  Apparently, such attacks are made preferentially on females who are laying and who may thus mother their offspring as a result.

In 2007, research suggested that in the ''[[Acilius]]'' [[genus]] of [[water beetle]]s (also known as "diving beetles"), an "evolutionary arms race" between the genders means that there is no courtship system for these beetles. "It's a system of rape. But the females don't take things quietly. They evolve counter-weapons." Cited mating behaviours include males suffocating females underwater till exhausted, and allowing only occasional access to the surface to breathe for up to six hours (to prevent them breeding with other males), and females which have a variety of body shapings (to prevent males from gaining a grip). Foreplay is "limited to the female desperately trying to dislodge the male by swimming frantically around."<ref>''[[The Times]]'', 25 June 2007 p.25, and online at [http://www.timesonline.co.uk/tol/news/uk/science/article1980376.ece "Not tonight, not ever. I’ve got a headache. Don’t come near me"]</ref>

Charles Siebert reports in his New York Times article ''Elephant Crackup?'' that:

{{quote|Since the early 1990’s, for example, young male elephants in Pilanesberg National Park and the Hluhluwe-Umfolozi Game Reserve in South Africa have been raping and killing rhinoceroses; this abnormal behaviour, according to a 2001 study in the journal Pachyderm, has been reported in ‘‘a number of reserves’’ in the region.|<ref>[http://www.nytimes.com/2006/10/08/magazine/08elephant.html?pagewanted=1&ei=5070&en=ccc63627f454863c&ex=1167282000 ''An Elephant Crackup?'', Charles Siebert, New York Times Magazine, October 8, 2006.]</ref>}}

===Sex between adults and juveniles===
It has also been recorded that certain species of [[Mole (animal)|mole]] will impregnate newborns of their own species. {{Fact|date=February 2007}} It is not clear if this is forceful or not. Similarly, the male [[stoat]] (Mustela erminea) will mate with infant females of their species.<ref>{{cite journal | author = Doncarlos, Michael W., Petersen, Jay S., Tilson, Ronald L. | title = Captive biology of an asocial mustelid; ''Mustela erminea'' | journal = Zoo Biology | volume = 5 | issue = 4 | pages = 363–370 | year = 1986 | doi = 10.1002/zoo.1430050407}}</ref> This apparently is a natural part of their reproductive biology - there is a delayed gestation period, so these females give birth the following year when they are fully grown.

A male spotted hyena which attempted to mate with a female which succeeded in driving it off, eventually turned to its ten-month-old cub, repeatedly [[mounting]] it and ejaculating on it.  The cub sometimes ignored this and sometimes struggled 'slightly as if in play'.  The mother did not intervene.<ref>H. Kruuk, ''The Spotted Hyena'', (University of Chicago Press, 1972), p. 232 </ref>

Infants and children in Bonobo societies often are involved in sexual behaviour..<ref name=ancestor>{{cite book |last=Dawkins |first=Richard |authorlink=Richard Dawkins |title=The Ancestor's Tale |year=2004 |publisher=Houghton Mifflin |chapter=Chimpanzees}}</ref>

===Sexual cannibalism===
{{main|Sexual cannibalism}}

Sexual cannibalism, which has been documented in [[arachnid]]s, [[insect]]s and [[amphipod]]s, is a phenomenon in which a female organism kills and consumes the male before, during, or after copulation. Although it does confer some known advantages to reproduction, whether or not the male is complicit has not been scientifically determined.

===Necrophilia===
[[Necrophilia]] in animals is where a living animal engages in a sexual act with a dead animal. In one of the most well-known examples, [[Kees Moeliker]] of the [[Rotterdam]] Natural History Museum, [[Netherlands]] observed sexual activities<ref>C.W. Moeliker.  [http://www.nmr.nl/nmr/binary/retrieveFile?instanceid=16&itemid=2574&style=home The first case of homosexual necrophilia in the mallard] (page 243-247)</ref> outside his office between a live [[duck]] and a dead one. Two male mallards which Moeliker believed were engaged in rape flight, a common motif in duck sexual behaviour, collided with his window. "When one died the other one just went for it and didn't get any negative feedback—well, didn't get any feedback," according to Moeliker, who described the event as "homosexual necrophilia." The case was reported scientifically in Deinsea 8-2001, along with photos.<ref>''DEINSEA'' [http://www.nmr.nl/nmr/pages/showPage.do?instanceid=16&itemid=1466&style=default states on its website]: ''"DEINSEA publishes original papers and short communications dealing with zoology, paleontology and (urban) ecology. Contributions that are entirely or partly based on material from the collection of the Natural History Museum Rotterdam (coll. NMR) and/or that are the result of research by NMR staff, have priority."'' The Mallard paper and photographs are [http://www.nmr.nl/nmr/pages/showPage.do?instanceid=16&itemid=1930&style=default available online] as a summary and also the paper [http://www.nmr.nl/nmr/binary/retrieveFile?instanceid=16&itemid=2574&style=home is available] in PDF format.<br />See also: {{cite news|url=http://education.guardian.co.uk/higher/research/story/0,9865,1432991,00.html|title=Necrophilia among ducks ruffles research feathers|date=[[2005-03-08]]|publisher=[[The Guardian]]|first=Donald|last=MacLeod|accessdate=2006-04-05}}</ref>, and earned Moeliker an [[Ig Nobel Prize]] in biology, awarded for humorous research.<ref>{{cite news|url=http://education.guardian.co.uk/higher/research/story/0,9865,1432991,00.html|title=Necrophilia among ducks ruffles research feathers|date=[[2005-03-08]]|publisher=[[The Guardian]]|first=Donald|last=MacLeod|accessdate=2006-04-05}}</ref>

Additionally, male [[cane toad]]s have been documented (in [[Cane Toads: An Unnatural History]]) engaging in copulation with dead toads and inanimate objects.

===Nasal sex===
[[Boto|Amazon River Dolphin]]s perform homosexual penetration of the [[Blowhole (biology)|blowhole]], the only known example of nasal sex.<ref>[http://www.timesonline.co.uk/tol/life_and_style/article1288633.ece Birds do it, bees do it . . . - Times Online<!-- Bot generated title -->]</ref><ref>[http://www.jimbo.info/weblog/2007/07/my-pet-gay-amazonian-dolphins.html#more My pet gay Amazonian dolphins practice 'skullfucking' - jimbo.info<!-- Bot generated title -->]</ref>