Similarly high rates of encounters have been observed among cougars and leopards, too. Female cheetahs and lions lick and rub the males' genitals as a part of their courtship ritual. Thinkstock The most instructive example may come from a study of two captive male brown bears published earlier this year in the journal Zoo Biology. When montane voles mate, they form no strong attachments, and separate after copulation. In a third of those copulations, they observed what they called female orgasmic responses: It's believed that it's the quantity of receptors, rather than the quantity of the hormones, that determines the mating system and bond-formation of either species. In News24 reported on the case of a Pretoria woman found guilty of having sex with two dogs. They can no longer assume social monogamy determines how genes are distributed in a species. Video footage of the intercourse was spread widely via the internet. As a result of the publicity the trial received, the state of Washington outlawed humans having sex with animals early the following year. In marine species with limited mobility and external fertilisation like corals , sea urchins and clams , the timing of the common spawning is the only externally visible form of sexual behaviour. But is that too narrow a view, when it's equally plausible that the rats just became bored with their food and wanted to try something new? Many socially monogamous species engage in extra-pair copulations , making them sexually non-monogamous. For starters, there is the issue of the transmission of diseases from one party to the other. Parental investment and reproductive success[ edit ] Main article: That's in part because this macaque behaviour is sometimes accompanied by the type of physiological changes seen in humans, such as increases in heart rate and vaginal spasms. Health24's Cybershrink explains why people become Zoophiles Like all paraphilias, zoophilia is unlikely to simply die out regardless of societal and legal opposition.