Editing Animal sexual behaviour (section)

===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>}}