Animal sexual behavior takes many different forms, even within the same species. Human sexual behavior or different human sexual practices encompass a wide range of activities such as strategies to find or attract partners ( Mating and display The Evolution of sexual reproduction is a major puzzle The first Fossilized evidence of sexually reproducing Organisms is from Eukaryotes of the Stenian In Biology, a species is one of the basic units of Biological classification and a Taxonomic rank. Researchers have observed monogamy, promiscuity, sex between species, sexual arousal from objects or places, sex apparently via duress or coercion, copulation with dead animals, homosexual, heterosexual and bisexual sexual behaviour, and situational sexual behaviour and a range of other practices among animals other than humans. Research is defined as Human activity based on Intellectual application in the investigation of Matter. Monogamy is the custom or condition of having only one mate in a Relationship, thus forming a Couple. Promiscuity refers to sexual behavior of a man or woman who casually has sex with many partners Rape, also referred to as Sexual assault, is an Assault by a person involving Sexual intercourse with or Sexual penetration of another person Necrophilia, also called thanatophilia and necrolagnia, is the sexual attraction to corpses Homosexuality refers to sexual behavior with or attraction to people of the same sex or to a Homosexual orientation. Heterosexuality refers to sexual behavior with or attraction to people of the opposite sex or to a heterosexual orientation Bisexuality refers to sexual behavior with or attraction to people of both sexes or to a bisexual orientation Human sexual behavior or different human sexual practices encompass a wide range of activities such as strategies to find or attract partners ( Mating and display Situational sexual behavior is sexual behavior of a kind that is different from what is usual for that person (or from what that person normally exhibits due to a social Related studies have noted diversity in sexed bodies and gendered behaviour, such as intersex and transgender animals. An organism's sex is defined by the gametes it produces males produce male gametes (spermatozoa or Sperm) while females produce female gametes (ova or Egg cells; individual Gender comprises a range of differences between men and women extending from the biological to the social Intersexuality is the state of a living thing of a gonochoristic species whose Sex chromosomes, Genitalia, and/or Secondary sex characteristics Transgender (trænzˈdʒɛndɚ from ( Latin) derivatives
The study of animal sexuality (and primate sexuality especially) is a rapidly developing field. It used to be believed that only humans and a handful of species performed sexual acts other than for procreation, and that animals' sexuality was instinctive and a simple response to the "right" stimulation (sight, scent). Reproduction is the Biological process by which new individual Organisms are produced Current understanding is that many species that were formerly believed monogamous have now been proven to be promiscuous or opportunistic in nature; a wide range of species appear both to masturbate and to use objects as tools to help them do so; in many species animals try to give and get sexual stimulation with others where procreation is not the aim; and homosexual behavior has now been observed among 1,500 species and in 500 of those it is well documented. Masturbation refers to Sexual stimulation especially of one's own genitals ( self masturbation) and often to the point of Orgasm, which A broader definition of a tool is an entity used to interface between two or more domains that facilitates more effective action of one domain upon the other 
In sociobiology and behavioural ecology, the term mating system is used to describe the ways in which animal societies are structured in relation to sexual behaviour. In Sociobiology and Behavioural ecology, a mating system is any of the ways in which animal societies are structured in relation to sexual behavior Sociobiology is a neo-Darwinian and Socialism Synthesis of Scientific disciplines that attempts to explain Social behavior Behavioral ecology is the study of the ecological and evolutionary basis for Animal behavior, and the roles of behavior in enabling an animal to adapt to In Sociobiology and Behavioural ecology, a mating system is any of the ways in which animal societies are structured in relation to sexual behavior The mating system specifies what males mate with what females under what circumstances.
The following are some of the mating systems generally recognised in humans and other animals:
Zoologists and biologists now have solid evidence that monogamous pairs of animals are not always sexually exclusive. Many animals that form pairs to mate and raise offspring regularly engage in sexual activities with extra-pair partners This includes previous exemplars such as swans. Swans are Birds of the family Anatidae, which also includes geese and Ducks Swans are grouped with the closely related geese in Sometimes these extra-pair sexual activities lead to offspring. Genetic tests frequently show that some of the offspring raised by a monogamous pair come from the female mating with an extra-pair male partner.  These discoveries have led biologists to adopt new ways of talking about monogamy:
Social monogamy refers to a male and female's social living arrangement (e. g. , shared use of a territory, behaviour indicative of a social pair, and/or proximity between a male and female) without inferring any sexual interactions or reproductive patterns. In humans, social monogamy equals monogamous marriage. Sexual monogamy is defined as an exclusive sexual relationship between a female and a male based on observations of sexual interactions. Finally, the term genetic monogamy is used when DNA analyses can confirm that a female-male pair reproduce exclusively with each other. A combination of terms indicates examples where levels of relationships coincide, e. g. , sociosexual and sociogenetic monogamy describe corresponding social and sexual, and social and genetic monogamous relationships, respectively.—Reichard, 2003, page 4
Whatever makes a pair of animals socially monogamous does not necessarily make them sexually or genetically monogamous. Social monogamy, sexual monogamy, and genetic monogamy can occur in different combinations.
Social monogamy is relatively rare in the animal kingdom. The actual incidence of social monogamy varies greatly across different branches of the evolutionary tree. Over 90 percent of avian species are socially monogamous. 
This stands in contrast to mammals. Only 3 percent of mammalian species are socially monogamous, although up to 15 percent of primate species are socially monogamous.  Social monogamy has also been observed in reptiles, fish, and insects.
Sexual monogamy is very rare among animals. The great majority of socially monogamous species engage in extra-pair copulations, making them sexually non-monogamous. For example, while over 90% of birds are socially monogamous, "on average, 30 percent or more of the baby birds in any nest [are] sired by someone other than the resident male. " Gowaty has estimated that, out of 180 different species of socially monogomous songbirds, only 10 percent are sexually monogamous. 
The incidence of genetic monogamy, determined by DNA fingerprinting, varies widely across species. For a few rare species, the incidence of genetic monogamy is 100 percent, with all offspring genetically related to the socially monogamous pair. But genetic monogamy is strikingly low in other species. Barash and Lipton note:
The highest known frequency of extra-pair copulations are found among the fairy-wrens, lovely tropical creatures technically known as Malurus splendens and Malurus cyaneus. More than 65 percent of all fairy-wren chicks are fathered by males outside the supposed breeding group.—Barash & Lipton, 2001, page 12
Such low levels of genetic monogamy have surprised biologists and zoologists, forcing them to rethink the role of social monogamy in evolution. They can no longer assume social monogamy determines how genes are distributed in a species. The lower the rates of genetic monogamy among socially monogamous pairs, the less of a role social monogamy plays in determining how genes are distributed among offspring. See also Evolution of Monogamy. The evolution of Monogamy refers to the natural history of Mating systems in which species reproduce by forming pairs to raise offspring
Polygamy is defined as a mating structure in which a single individual of one gender has exclusive access to several individuals of the opposite gender. It takes two main forms - polygyny and polyandry. As polygyny is the most common form of polygamy among vertebrates (including humans, to some extent), it has been studied far more extensively than polyandry.
In some species, notably those with harem male structures, only one of a few males in a group of females will mate. HAREM is the first evaluation contest of Named entity recognition (NER for Portuguese and its call for participation was announced in September 2004 This is also known as polygyny in sociobiology. Polygyny (which comes from neo- Greek: πολύ poly "many" + γυνή gyny "woman" is a specific form of Polygamy, Sociobiology is a neo-Darwinian and Socialism Synthesis of Scientific disciplines that attempts to explain Social behavior  Should the active male be driven out, killed, or otherwise removed from the group, in a number of species the new male will ensure that breeding resources are not wasted on another male's young.  The new male may achieve this in many different ways, including:
Two examples of systems in primates are promiscuous mating chimpanzees and bonobos. Promiscuity refers to sexual behavior of a man or woman who casually has sex with many partners Chimpanzee (often shortened to chimp) is the common name for the two extant Species of Apes in the Genus Pan. The Bonobo (bə'noʊboʊ Pan paniscus) until recently usually called the Pygmy Chimpanzee (and less often the Dwarf or Gracile Chimpanzee These species live in social groups consisting of several males and several females. Each male copulates with many females, and vice versa. In bonobos, the amount of promiscuity is particularly striking because bonobos use sex to alleviate social conflict as well as to reproduce.
Many animal species have specific mating (or breeding) seasons. These are often associated with changes to herd or group structure, and behavioral changes, including territorialism amongst individuals. These may be annual (eg wolves), biannual (eg dogs) or more frequently (eg horses). During these periods, females of most species are more mentally and physically receptive to sexual advances, a period often described as being "in season" or "in heat", but outside them animals still engage in sexual behaviors, and such acts as do occur are not necessarily harmful. 
The field of study of sexuality in non-human species has been a long standing taboo, with researchers either failing to observe or mis-categorizing and mis-describing sexual behavior which does not meet their preconceptions. A taboo is a strong Social prohibition (or ban) against words objects actions or discussions that are considered undesirable or offensive by a group culture (See: Observer bias) More current research provides views such as that of the Norwegian Natural History Museum, which in 2006 held an exhibition on animal sexuality:
Many researchers have described homosexuality as something altogether different from sex. Observer Effect is the title of the 87th episode from the television series Star Trek Enterprise. They must realise that animals can have sex with who they will, when they will and without consideration to a researcher's ethical principles.
An example of overlooking behaviour relates to descriptions of giraffe mating:
When nine out of ten pairings occur between males, "[e]very male that sniffed a female was reported as sex, while anal intercourse with orgasm between males was only [categorized as] 'revolving around' dominance, competition or greetings. The giraffe ( Giraffa camelopardalis) is an African Even-toed ungulate Mammal, the tallest of all land-living Animal Species Anal sex most often refers to the sex act involving insertion of the Penis into the Rectum. An orgasm (sexual climax is the conclusion of the plateau phase of the sexual response cycle, and may be experienced by both males and females
It is a common myth that animals do not (as a rule) have sex for pleasure, or alternatively that humans (and perhaps cats, dolphins and one or two species of primate) are the only species which do. This is sometimes formulated "animals mate only for reproduction".
Science cannot say at present conclusively what animals do or do not find "pleasurable", a question considered in more depth under Emotion in animals. Emotion in animals considers the question of whether certain species of non-human Animals feel emotions in the sense that humans understand it The urban myth site Snopes.com considers this particular view in depth. Snopes (ˈsnoʊps also known as the Urban Legends Reference Pages, is a Web site that is the most widely-known resource for validating or debunking Urban legends Its conclusions are broadly that the statement is true, but only using a very specific definition of "sex for pleasure" [italics in original], in which sexual acts tied to a reproductive cycle or for which an alternative explanation can be asserted, are ignored, as is all sexual activity that does not involve penetration. Animals put themselves at risk to engage in sex, and as a result, most species have evolved sexual signals (usually scent and behavior) to indicate the presence of receptive periods. During these, sex is sought, and outside these it is usually not sought (or is sought but not permitted). Snopes comments that this is not in fact a reflection of whether sex is pleasurable or not, but rather a reflection of whether individuals have sex at arbitrary times. They conclude:
A 2006 Danish Animal Ethics Council report which examined current knowledge of animal sexuality in the context of legal queries concerning sexual acts by humans, has the following comments, primarily related to domestically common animals:
Even though the evolution-related purpose of mating can be said to be reproduction, it is not actually the creating of offspring which originally causes them to mate. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. The Kingdom of Denmark ( ˈd̥ænmɑɡ̊ (archaic ˈd̥anmɑːɡ̊ commonly known as Denmark, is a country in the Scandinavian region of northern Europe It is probable that they mate because they are motivated for the actual copulation, and because this is connected with a positive experience. It is therefore reasonable to assume that there is some form of pleasure or satisfaction connected with the act. This assumption is confirmed by the behavior of males, who in the case of many species are prepared to work to get access to female animals, especially if the female animal is in oestrus, and males who for breeding purposes are used to having sperm collected become very eager, when the equipment they associate with the collection is taken out.—
There is nothing in female mammals’ anatomy or physiology, that contradicts that stimulation of the sexual organs and mating is able to be a positive experience. For instance, the clitoris acts in the same way as with women, and scientific studies have shown that the success of reproduction is improved by stimulation of clitoris on (among other species) cows and mares in connection with insemination, because it improves the transportation of the sperm due to contractions of the inner genitalia. This probably also concerns female animals of other animal species, and contractions in the inner genitals are seen e. g. also during orgasm for women. It is therefore reasonable to assume that sexual intercourse may be linked with a positive experience for female animals.—
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 behavior in all stallions that does not reduce semen production or performance in the breeding shed, and thus the use of devices to prevent such behavior is strongly discouraged and can be harmful to the stallion. " Likewise the paper "Sexual Behavior - Current Topics in Applied Ethology and Clinical Methods" by Sue McDonnell of the Equine Behavior Laboratory, University of Pennsylvania School of Veterinary Medicine states:
One example is the behavior known within the horse breeding industry as masturbation. This involves normal periodic erections and penile movements. This behavior, both from the descriptive field studies cited above and in extensive study of domestic horses, is now understood as normal, frequent behavior of male equids.—
Attempting to inhibit or punish masturbation, which is still a common practice of horse managers regionally around the world, often leads to increased masturbation and disturbances of normal breeding behavior (McDonnell and Hinze, in preparation). 
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 here. Also, another video (explicit) of a kangaroo performing autofellatio can be found here, and a dog balancing on rear legs in order to masturbate with both front paws, here. Autofellatio is the act of oral stimulation of one's own Penis as a form of Masturbation.
The female porcupine has been observed to use a stick as a vibrator, holding one end of a stick and walking around, straddling it as it bumped against the ground and vibrated against her genitalia. Porcupines are Rodents with a coat of sharp spines or quills that defend them from predators Vibrators are devices intended to vibrate against the body and stimulate the nerves for a relaxing and pleasurable feeling  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:
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. Henry Havelock Ellis ( February 2, 1859 - July 8, 1939) was a British sexologist, physician and social reformer 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.
In his 1999 book, Biological exuberance, Bruce Bagemihl PhD documents (p. 71, 209-210) that:
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).
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.
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.
Apes and Monkeys use a variety of objects to masturbate with and even deliberately create implements for sexual stimulation [. . . ] often in highly creative ways.
Petter Bøckman of the Norwegian Natural History Museum commented (in respect of a 2006 exhibition on homosexuality in the animal kingdom) that:
Masturbation is common in the animal kingdom . Against Nature? is a controversial exhibition on Homosexuality in animals made by The Natural History Museum University of Oslo, Norway. . . We have a Darwinist mentality that all animals only have sex to procreate. Darwinism is a term used for various different movements or concepts related to a greater or lesser extent to Charles Darwin 's work on Evolution. 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 dildos of wood and bark. A dildo is a Sex toy, often explicitly Phallic in appearance intended for bodily penetration during self-administered Masturbation
Animals of several species are documented as engaging in both auto-fellatio and oral sex. Autofellatio is the act of oral stimulation of one's own Penis as a form of Masturbation. Oral sex refers to sexual activities involving the use of the Mouth, and may include use of the Tongue, Teeth, and Throat, in order Although easily confused by lay-people, this is a separate and sexually oriented behavior, distinct from non-sexual grooming or the investigation of scents. In Social animals and humans social grooming or allogrooming is an activity in which individuals in a group clean or maintain each other's body or appearance
Auto-fellatio or oral sex in animals is documented in goats, primates, hyaenas and sheep. The domestic goat ( Capra aegagrus hircus) is a subspecies of goat Domesticated from the Wild goat of Southwest Asia and Eastern Europe A primate is a member of the biological order Primates ( Latin: "prime first rank" the group that contains Lemurs the Aye-aye The Hyaenidae is a Mammalian family of order Carnivora. The Hyaenidae family native to both African and Asian continents consists of four (see section Masturbation for details).
The presence of same-sex sexual behavior was not scientifically observed on a large scale until recent times. The Mallard ( Anas platyrhynchos) probably the best-known and most recognizable of all ducks is a Dabbling duck which breeds throughout the Temperate Human sexual behavior or different human sexual practices encompass a wide range of activities such as strategies to find or attract partners ( Mating and display Homosexual behaviour does occur in the animal kingdom outside humans, especially in social species, particularly in marine birds and mammals, monkeys, and the great apes. Homosexual behaviour has been observed among 1,500 species, and in 500 of those it is well documented. 
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.
Georgetown University professor Janet Mann has specifically theorised that homosexual behaviour, at least in dolphins, is an evolutionary advantage that minimizes intraspecies aggression, especially among males. Georgetown University is a Jesuit Private university located in Georgetown Washington D Dolphins are Marine mammals that are closely related to Whales and Porpoises There are almost forty species of dolphin in seventeen genera.
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. . .
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 . 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 horses are apparently well known by wildlife specialists. The moose (North America or elk (Europe Alces alces, is the largest extant Species in the Deer family. The horse ( Equus caballus) is a hoofed ( Ungulate) Mammal, one of eight living species of the family Equidae. 
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".  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 considered below. Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus
Hybrid offspring can result from two organisms of distinct but closely related parent species, although the resulting offspring is not always fertile. In Biology, hybrid has two meanings The first meaning is the result of interbreeding between two animals or plants of different taxa. Fertility is the natural capability of giving life As a measure "Fertility Rate" is the number of children born per couple person or population According to the definition of a species, If two organisms cannot or will not mate and produce a fertile offspring, they are different species. The mule, for example (a horse/donkey cross) is normally sterile, whilst the liger (lion/tiger cross) has fertile females and sterile males. In its common modern meaning a mule is the offspring of a male Donkey and a female Horse, which is classified as a kind of F1 hybrid. The liger, is a hybrid cross between a male Lion and a female Tiger (i 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".
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. A Grizzly–polar bear hybrid is a rare Ursid hybrid that has occurred both Stories without links will be removed'. News stories must be in English 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. 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 ethologists such as Kohler, Gerald Durrell and Desmond Morris, as well as authoritative researchers such as Birute Galdikas who studied orangutans in Borneo. Ethology ( from Greek ἦθος ethos, "character" and λόγος logos, "knowledge") is the scientific study of Animal Gerald ('Gerry' Malcolm Durrell OBE ( January 7, 1925 &ndash January 30, 1995) was a naturalist, Zookeeper For the Australian rugby league footballer coach and administrator see Des Morris Desmond John Morris (born 24 January 1928 Biruté Marija Filomena Galdikas, OC PhD (born, Wiesbaden, Germany) is a Primatologist, Conservationist, Ethologist The orangutans are two Species of great apes known for their intelligence long arms and reddish-brown hair Borneo is the third largest island in the world and is located at the centre of Maritime Southeast Asia. Philosopher and animal welfare activist Peter Singer reports:
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. Animal welfare refers to the viewpoint that it is morally acceptable for humans to use nonhuman animals for food in animal research, as clothing and in entertainment Peter Albert David Singer (born July 6, 1946 in Melbourne, Victoria, Australia) is an Australian philosopher. 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'.—
the orangutan lost interest before penetration took place—
In some penguin species, the females, even when in a committed relationship, will exchange sexual favours with strange males for the pebbles they need to build their nests. Penguins ( order Sphenisciformes, family Spheniscidae) are a group of aquatic, flightless Birds living almost A pebble is a clast of rock with a Particle size of 4 to 64 Millimeters based on the Krumbein phi scale of Sedimentology A nest is a place of refuge to hold an animal's eggs and/or provide a place to raise their offspring 
Although not often reported, it appears animals, or primates at the least, are able to sexualize inanimate objects similar to the way human beings sexualize the objects of their sexual fetishes. Sexual fetishism, or erotic fetishism, is the Sexual attraction to materials and objects not conventionally viewed as being sexual in nature 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.
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:
A male chimpanzee raised in captivity developed a bit of a shoe fetish, masturbating obsessively by rubbing his caretaker's leather boot.
The sexualization of objects or locations is also well recognized in the breeding world. So for example, stallions may often 'drop' (become 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. An artificial vagina is a device designed to simulate the female sex organ
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'. Classical Conditioning (also Pavlovian or Respondent Conditioning) is a form of Associative learning that was first demonstrated by Ivan Pavlov Human fetishism can also be traced back to similar or near-identical conditioning: likewise based upon the Pavlovian association between an erotic sensation or anticipation, and objects which become mentally associated with that activity. Pelvic congestion is a condition of temporary uncomfortable and sometimes painful condition of both men and women usually caused by prolonged Sexual arousal.
A study by Platt, Khera and Deaner at Duke University North Carolina (reported in Current Biology and online 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. Current Biology is a scientific journal that covers all areas of Biology, especially Molecular biology, Cell biology, Genetics, 
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 behaviors 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 (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 pandas to mate in captivity have been very common. The Giant Panda ( Ailuropoda melanoleuca, "black-and-white cat-foot" is a Mammal classified in the Bear family ( Ursidae) native to However, showing young male pandas "panda pornography" is widely credited with a recent population boom among pandas in zoos. 
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. Sociobiological theories of rape are theories that explore to what degree if any evolutionary adaptations influence the psychology of rapists A notable example is bottlenose dolphins, where at times, gangs of bachelor males 'corner' females. The Bottlenose Dolphin is one of the most common and well-known Dolphins. A bachelor herds is a gathering of (usually juvenile male animals who are still sexually immature or of 'harem'-forming animals who have been thrown out of their parent groups but not  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.  The behavior is also common in some arachnids (spiders), notably those whose females eat the males during sex if not tricked with food and/or tied down with threads, and in some herbivorous herd species or species where males and females are very different in size, where the male dominates sexually by sheer force and size. Arachnids are a class ( Arachnida) of joint-legged Invertebrate Animals in the subphylum Chelicerata. Herbivory is a form of Predation in which an Organism, known as a herbivore, consumes principally Autotrophs ref name=Campbell>Campbell
Some species of birds appear to combine sexual intercourse with apparent violent assault; these include ducks, geese, and white-fronted bee-eaters. For duck as a food see Duck (food; for other meanings see Duck (disambiguation. Goose (plural geese) is the English name for a considerable number of Birds belonging to the family Anatidae. The White-Fronted Bee-eater, Merops bullockoides, is a species of Bee-eater widely distrubted in sub-equatorial Africa. According to Emlen and Wrege (1986) 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 beetles (also known as "diving beetles"), an "evolutionary arms race" between the genders means that there is no courtship system for these beetles. This article is about the Roman family For the genus of Diving beetles see Acilius (genus Acilius (fem A genus (plural genera from Γένος Latin genus "descent family type gender" is a low-level Taxonomic A water beetle is a Beetle adapted to living in water several different types are known most in or on Fresh water. "It's a system of rape. But the females don't take things quietly. They evolve counter-weapons. " Cited mating behaviors 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. "
Charles Siebert reports in his New York Times article Elephant Crackup? that:
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 behavior, according to a 2001 study in the journal Pachyderm, has been reported in ‘‘a number of reserves’’ in the region.—
It has also been recorded that certain species of mole will impregnate newborns of their own species. It is not clear if this is forceful or not. Similarly, the male stoat (Mustela erminea) will mate with infant females of their species.  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. 
Infants and children in Bonobo societies often are involved in sexual behavior. . 
Sexual cannibalism, which has been documented in arachnids, insects and amphipods, is a phenomenon in which a female organism kills and consumes the male before, during, or after copulation. This article is about arthropod behavior for the human psychological disorder see sexually motivated cannibalism Sexual cannibalism is a special Arachnids are a class ( Arachnida) of joint-legged Invertebrate Animals in the subphylum Chelicerata. Insects ( Class Insecta) are a major group of Arthropods and the most diverse group of Animals on the Earth with over a million described Amphipoda (amphipods are an order of animals that includes over 7000 described Species of Shrimp -like Crustaceans ranging from 1 mm to 140 mm Although it does confer some known advantages to reproduction, whether or not the male is complicit has not been scientifically determined.
Necrophilia in animals is where a living animal engages in a sexual act with a dead animal. Necrophilia, also called thanatophilia and necrolagnia, is the sexual attraction to corpses In one of the most well-known examples, Kees Moeliker of the Rotterdam Natural History Museum, Netherlands observed sexual activities outside his office between a live duck and a dead one. Rotterdam (pronounced) is the 2nd-largest City by population in the Netherlands, located in the province of The Netherlands ( Dutch:, ˈnedərlɑnt is the European part of the Kingdom of the Netherlands, which consists of the Netherlands the Netherlands For duck as a food see Duck (food; for other meanings see Duck (disambiguation. Two male mallards which Moeliker believed were engaged in rape flight, a common motif in duck sexual behavior, 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. , and netted Moeliker an Ig Nobel Prize in biology, awarded for humorous research. The Ig Nobel Prizes are a Parody of the Nobel Prizes and are given each year in early October — around the time the recipients of the genuine Nobel Prizes are 
Additionally, male cane toads have been documented (in Cane Toads: An Unnatural History) engaging in copulation with dead toads and inanimate objects. Cane Toads An Unnatural History ( 1988) is a 47-minute Documentary film about the introduction of Cane Toads to Australia.
The Bonobo, which has a peaceful, egalitarian and matriarchal society, is a fully bisexual species — both males and females engage in sexual behaviour with the same and the opposite sex, with females being particularly noted for engaging in sexual behaviour with each other and at up to 75% of sexual activity being bisexual. The Bonobo (bə'noʊboʊ Pan paniscus) until recently usually called the Pygmy Chimpanzee (and less often the Dwarf or Gracile Chimpanzee Matriarchy is a term which is applied to gynocentric form of Society, in which the leading role is by the Female and especially by the Mothers Bonobos often use sexual activity to prevent violence and conflict. 
Some black swans of Australia form sexually active male-male mated pairs and steal nests, or form temporary threesomes with females to obtain eggs, driving away the female after she lays the eggs. A threesome is a form of Group sex involving three people of any gender combination More of their cygnets survive to adulthood than those of different-sex pairs possibly due to their superior ability to defend large portions of land.
In early February 2004 the New York Times reported that a male pair of chinstrap penguins named Roy and Silo in the Central Park Zoo in New York City were partnered and had successfully hatched a female chick from an egg. "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " The Chinstrap Penguin ( Pygoscelis antarcticus) is a species of Penguin which is found in the South Sandwich Islands, Antarctica the South Orkneys Roy and Silo were a Chinstrap penguin couple in New York 's Central Park Zoo. The Central Park Zoo is located in Central Park in New York City and run by the Wildlife Conservation Society. The City of New York Other penguins in New York have also been reported to be forming same-sex pairs.
Zoos in Japan and Germany have also documented male penguin couples. For a topic outline on this subject see List of basic Japan topics. Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. The couples have been shown to build nests together and use a stone to replace an egg in the nest. Researchers at Rikkyo University in Tokyo, found twenty such pairs at sixteen major aquariums and zoos in Japan. also known as Saint Paul's University is a prestigious Japanese Christian University in Ikebukuro, Tokyo. officially, is one of the 47 prefectures of Japan and located on the eastern side of the main island Honshū. Bremerhaven Zoo in Germany attempted to break up the male couples by importing female penguins from Sweden and separating the male couples; they were unsuccessful. "Sverige" redirects here For other uses see Sweden (disambiguation and Sverige (disambiguation. The zoo director stated the relationships were too strong between the couples.
Recently, a mated pair of swans in Boston were found to both be female. Swans are Birds of the family Anatidae, which also includes geese and Ducks Swans are grouped with the closely related geese in They too had attempted to raise eggs together. 
Studies have shown that ten to fifteen percent of female western gulls in some populations in the wild prefer other females.
As many as 19% of Mallard pairs in a given population have been observed to consist of male-male homosexuals. 
Whip-tailed lizard females have the ability to reproduce through parthenogenesis and as such males are rare and sexual breeding non-standard. Cnemidophorus is a Genus of Lizards which belong to the family of Teiidae, which are commonly referred to as Whiptail Lizards Parthenogenesis (from the Greek παρθένος parthenos, "virgin" + γένεσις genesis, "creation" is an asexual form Females engage in sexual behavior to stimulate ovulation, with their behavior following their hormonal cycles; during low levels of estrogen, these (female) lizards engage in "masculine" sexual roles. Note This article deals primarily with Human ovulation nonhuman Animal ovulation is touched on briefly at the conclusion Those animals with currently high estrogen levels assume "feminine" sexual roles.
Lizards that perform the courtship ritual have greater fecundity than those kept in isolation due to an increase in hormones triggered by the sexual behaviors. So, even though asexual whiptail lizards populations lack males, sexual stimuli still increase reproductive success.
From an evolutionary standpoint these females are passing their full genetic code to all of their offspring rather than the 50% of genes that would be passed in sexual reproduction. eVolution is the third Album by eLDee, it was due to be released in 2008 Certain species of gecko also reproduce by parthenogenesis. Geckos are small to average sized Lizards belonging to the family Gekkonidae which are found in warm climates throughout the world
Penis fencing is a mating behavior engaged in by certain species of flatworm, such as Pseudobiceros hancockanus. Penis fencing is a Mating behavior engaged in by certain species of Flatworm, such as Pseudobiceros hancockanus The flatworms (Phylum Platyhelminthes from the Greek πλατύ platy, meaning "flat" and ἕλμινς (root ἑλμινθ- helminth- Species which engage in the practice are hermaphroditic, possessing both eggs and sperm-producing testes. 
Child-bearing, while necessary for the continuation of a species, requires considerable resources from the mother. Thus, from a biological point of view, it is preferable to be the father rather than the mother.
The species "fence" using two-headed dagger-like penises which are pointed, and white in color. The "winner" is the organism that inseminates the other. The sperm is absorbed through pores in the skin, causing fertilization in the "loser".
An October 2003, study by Dr. Year 2003 ( MMIII) was a Common year starting on Wednesday of the Gregorian calendar. Charles E. Roselli et al. (Oregon Health & Science University) states that homosexuality in male sheep (found in eight percent of rams) is associated with a region in the rams' brains which the authors call the "ovine Sexually Dimorphic Nucleus" (oSDN) which is half the size of the corresponding region in other male sheep. Oregon Health & Science University ( OHSU) is a public University in Oregon with a main campus including three Hospitals in Portland
However, some view this study to be flawed in that the determination of homosexuality within the sheep, (sample population of twenty-seven for the study), was to have animals who were unable to mount female ewes placed in a cage with two stanchioned males and two unstanchioned females (that is, the males could not move or struggle while the females could). Given the aggressive nature of the sheep copulation, the uneven treatment of males and females, many see this as simply evidence that the sheep in question were unable to be aggressive enough to mount females. Some say that the results were situational sexuality, unlike the bonds seen in human homosexuality. However the physical brain anatomy of the rams that preferred males were different.
The scientists found that, "The oSDN in rams that preferred females was significantly larger and contained more neurons than in male-oriented rams and ewes. Neurons (ˈnjuːɹɒn also known as neurones and nerve cells) are responsive cells in the Nervous system that process and transmit information In addition, the oSDN of the female-oriented rams expressed higher levels of aromatase, a substance that converts testosterone to estradiol, an estrogen hormone believed to facilitate typical male sexual behaviors. Testosterone is a Steroid hormone from the Androgen group In mammals testosterone is primarily secreted in the testes of males and the Ovaries Estradiol (17β-estradiol (also oestradiol) is a Sex hormone. Estrogens (US otherwise oestrogens or œstrogens) are a group of Steroid compounds named for their importance in the Estrous cycle, Hormones (from Greek ὁρμή - "impetus" are chemicals released by cells that affect cells in other parts of the body Aromatase expression was no different between male-oriented rams and ewes. "
"The dense cluster of neurons that comprise the oSDN express cytochrome P450 aromatase. Cytochrome P450 (abbreviated CYP, P450, infrequently CYP450) is a very large and diverse superfamily of Hemoproteins found in all Domains Aromatase mRNA levels in the oSDN were significantly greater in female-oriented rams than in ewes, whereas male-oriented rams exhibited intermediate levels of expression. " These results suggest that ". . . naturally occurring variations in sexual partner preferences may be related to differences in brain anatomy and its capacity for estrogen synthesis. " As noted previously, given the potential unagressiveness of the male population in question, the differing aromatase levels may also have been evidence of aggression levels, not sexuality. The results of this study have not been confirmed by others.
The female Spotted Hyena has a unique urinary-genital system, closely resembling the penis of the male, called a pseudo-penis. The Spotted Hyena, or Laughing Hyena, ( Crocuta crocuta) is a carnivorous Mammal of the family Hyaenidae. A pseudo-penis is a term used of any structure found on an animal that while superficially appearing to be a Penis, is derived from a different developmental path The family structure is matriarchal and dominance relationships with strong sexual elements are routinely observed between related females.
They are notable for using visible sexual arousal as a sign of submission and not dominance, in males as well as females (females have a sizable erectile clitoris), to the extent that biologist Robert Sapolsky speculates that in order to facilitate this, their sympathetic and parasympathetic nervous systems may be partially reversed in respect to their reproductive organs. The clitoris is a sexual organ that is present only in Female Mammals In humans the visible button-like portion is located near the Anterior Robert Maurice Sapolsky (born 1957) is the John A and Cynthia Fry Gunn Professor of Biological Sciences and Professor of Neurology and Neurological Sciences and by courtesy The parasympathetic Nervous system ( PSNS) is a division of the Autonomic nervous system (ANS along with the Sympathetic nervous system 
Bottlenose Dolphin males have been observed working in pairs to follow and/or restrict the movement of a female for weeks at a time, waiting for her to become sexually receptive. The Bottlenose Dolphin is one of the most common and well-known Dolphins. The same pairs have also been observed engaging in intense sexual play with each other.
Janet Mann, a professor of biology and psychology at Georgetown University, argues that the common same-sex behavior among male dolphin calves is about bond formation and benefits the species evolutionarily. They cite studies that have shown the dolphins later in life are bisexual and the male bonds forged from homosexuality work for protection as well as locating females to reproduce with.
Seahorses, long upheld as monogamous and mating for life, are identified as "promiscuous, flightly, and more than a little bit gay" according to research published in 2007. Seahorses are a Genus ( Hippocampus ') of fish belonging to the family Syngnathidae, which also includes Pipefish and Leafy Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. 
Scientists at 15 aquariums studied 90 seahorses of 3 species. An aquarium (plural aquariums or aquaria) is a Vivarium consisting of at least one transparent side in which Water -dwelling Plants In Biology, a species is one of the basic units of Biological classification and a Taxonomic rank. Of 3168 sexual encounters, 37% were same sex acts. Flirting was common (up to 25 potential partners a day of both genders); only one species (the British Spiny Seahorse) included faithful representatives, and for these 5 of 17 were faithful, 12 were not. Bisexuality was widespread and considered "both a great surprise and a shock", with big bellied seahorses of both genders not showing partner preference. 1986 contacts were male-female, 836 were female-female and 346 were male-male.
Male lions often lead their social groups jointly with one or more of their brothers. The lion ( Panthera leo) is a member of the family Felidae and one of four Big cats in the Genus Panthera. To ensure loyalty, the male co-leaders will "strengthen the bonds by often having sex with each other. "
Looking back in history, current research into human evolution tends to confirm that in some cases, interspecies sexual activity may have been responsible for the evolution of entire new species. The Humanzee (also known as the Chuman or Manpanzee) is a hypothetical Chimpanzee / Human hybrid. Human evolution, or anthropogenesis, is the part of biological Evolution concerning the emergence of Homo sapiens as a distinct Species Analysis of human and animal genes in 2006 provides strong evidence that after humans had diverged from apes, interspecies mating nonetheless occurred regularly enough to change certain genes in the new gene pool:
A new comparison of the human and chimp genomes suggests that after the two lineages separated, they may have begun interbreeding. History See also History of genetics The existence of genes was first suggested by Gregor Mendel (1822-1884 who in the 1860s studied inheritance Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus In Population genetics, a gene pool is the complete set of unique Alleles in a Species or Population. Chimpanzee (often shortened to chimp) is the common name for the two extant Species of Apes in the Genus Pan. In classical genetics the genome of a Diploid Organism including Eukarya refers to a full set of chromosomes or genes in a Gamete, thereby [. . . ] A principal finding is that the X chromosomes of humans and chimps appear to have diverged about 1. The X chromosome is one of the two sex-determining Chromosomes in many animal species including mammals (the other is the Y chromosome) Genetic divergence is the process of one species diverging over time into more than one species 2 million years more recently than the other chromosomes.
The research suggests that:
There were in fact two splits between the human and chimp lineages, with the first being followed by interbreeding between the two populations and then a second split. The suggestion of a hybridization has startled paleoanthropologists, who nonetheless are "treating the new genetic data seriously. Paleoanthropology, which combines the disciplines of Paleontology and Physical anthropology, is the study of ancient humans as found in Fossil hominid
The Washington Post comments, "If this theory proves correct, it will mean modern people are descended from something akin to chimp-human hybrids. The Washington Post is the largest and most circulated Newspaper in Washington D "
Information about animal sexuality frequently arises as a persuasive device in arguments regarding human sexuality. Originally, the lack of documented animal sexual behavior deviant from heterosexual sexual monogamy was used to argue that the dominant heterosexual monogamy of most modern human societies is more natural and acceptable. Likewise, the lack of documented sex between animals for the purpose of pleasure was used to promote the moral standard of reserving sex primarily for procreation. Proponents of alternate sexuality attribute this early lack of documented evidence to an observer bias in researchers, who, they argue, tended to interpret sexual behavior inconsistent with their values as other behavior. Observer Effect is the title of the 87th episode from the television series Star Trek Enterprise.
With increasing published evidence of different types of sexual behavior between animals, arguments for heterosexual monogamy in human society have moved towards characterizing these behaviors as resulting from differences between humans and animals, and in particular on ambiguity in motivation and subjective experience in animals, which is difficult to study. Arguments identifying human and animal behavior are characterized as anthropomorphism, and in some cases an opposite observer bias is attributed to researchers. Anthropomorphism is the attribution of uniquely Human characteristics to non-human creatures and beings natural and supernatural phenomena material states and objects Supporters of alternate sexuality embrace the new research as confirmation of the naturalness of alternate sexual behavior and evidence of its long-term feasibility and utility.