Homosexuality in the Animal Kingdom (#125)

For a very long time, scientists have known that animals engage in sexual behaviour with individuals of the same sex. 

In 1910, a team of scientists set off on the Terra Nova Expedition to explore Antarctica. Among them was George Murray Levick, a zoologist and photographer who would be the first researcher to study the world's largest Adélie penguin colony. 

In his notebooks, he chronicled their sexual behaviour, including sex between male birds. However, none of these notes would appear in Levick's published papers. Concerned by the graphic content, he only printed 100 copies of Sexual Habits of the Adélie Penguin to circulate privately. The last remaining copy was recently unearthed providing valuable insights into animal homosexuality research.

But forays into animal homosexuality research long predate Levick, with observations published as far back as the 1700s and 1800s. More than 200 years later, research has moved past some of the taboos those early researchers faced and shown that homosexuality is much more common than previously thought.

Such same-sex sexual behaviour can include, for example, mounting, courting, from primates to sea stars, bats to damselflies, snakes to nematode worms.

Same-sex behaviour ranging from co-parenting to mounting, courting through songs and other signals, genital licking or releasing sperm, and has been observed in over 1,500 animal species with likely many more as researchers begin to look for the behaviour explicitly. Homosexuality is widespread, with bisexuality even more prevalent across species.

Same-sex relationships among other animal species showcase that sexuality is a spectrum and a natural part of the animal kingdom – while also reminding everyone that, like us, every animal is an individual with a wide range of emotions and the ability and desire to form relationships.

Here is just a small list of some of my favourite animals that have been shown to engage in queer activity. Starting with one of the first ever recording, though you might not guess which animal it was discovered in:

Scarab Beetles

In 1896, French entomologist Henri Gadeau de Kerville published one of the first scientific illustrations of animal homosexuality. His drawing depicted two male scarab beetles copulating and was part of a wave of descriptions of same-sex behaviour in insects that set the stage for animal observations in the 1900s.

Penguins

Penguins are famously monogamous, known to link up with one partner for life. Among these long-lasting, loving relationships are countless same-sex couples sticking together through thick and thin.

Since George Murray Levick observations mentioned earlier, thousands more same-sex penguin couples have been noted. Well known among them are Ronnie and Reggie, a gay couple at London Zoo, as well as Sphen and Magic, two male Gentoo penguins, recently made headlines when they 'adopted' an egg. Gentoos are closely related to Adélie penguins, the species Levick first observed in 1911. After the two penguins bonded and began creating a nest, zookeepers at the Sea Life Sydney Aquarium decided to give them an egg that had been abandoned by a pair of heterosexual penguins in the group. On October 19, 2018, Baby Sphengic was born.

There was even Roy and Silo, two male chinstrap penguins at New York's Central Park Zoo have been inseparable for six years now. They display classic pair-bonding behaviour—entwining of necks, mutual preening, flipper flapping, and the rest. They also have sex, while ignoring potential female mates.

Swans

Like many birds, swans are monogamous and stick with one partner for years. Many of them choose a same-sex partner. In fact, around 20 percent of swan couples are homosexuals - and they often start families together. Sometimes, one swan in a male couple will mate with a female, and then drive her away once she's laid a clutch of eggs. In other cases, they adopt abandoned eggs.

Albatross

The Layson albatross, which nests in Hawaii, is known for its large number of homosexual partnerships. Around 30 percent of pairings on the island of Oahu are made up of two females. They are monogamous, and usually stay together for life - as it takes two parents to successfully rear a chick together. The chicks are often fathered by males that are already in another committed relationship.

Japanese Macaques

These primates often display bisexual behaviour, exploring sexual activity with both the same and opposite sex – although these intimate acts would definitely be considered x-rated if they were observed in humans! Primatologist Amy Parish argues that female macaques may enhance their social position through homosexual intimacy which in turn influences breeding success. Parish says, "Taking something that's nonreproductive, like mounting another female—if it leads to control of a resource or acquisition of a resource or a good alliance partner, that could directly impact your reproductive success."

On the other hand, they could just be enjoying themselves! Female Japanese macaques sometimes pursue same-sex sexual partners even if a male macaque is showing interest in them – they just prefer to get together with another female. 

But while males usually only do so for a night, females form intense bonds with each other and are usually monogamous. In some macaque populations, homosexual behaviour among females is not only common, but the norm. When not mating, these females stay close together to sleep and groom, and defend each other from outside enemies.

Bonobos

The bonobo, an African ape closely related to humans, has an even bigger sexual appetite and are very well known for seeking sexual pleasure. They copulate frequently, including with the same sex - studies even suggest that 75 percent of bonobo sex is nonreproductive and that nearly all bonobos are bisexual. They do so mainly for pleasure - the species is often called the "make love, not war" primate - as it is believed that bonobos use sex to resolve conflicts between individuals, climb he social ladder and also bond with each other. About two-thirds of homosexual activities happen among females, but also males enjoy a roll in the grass with each other.

Spider Monkeys

Spider monkeys are New World primate species for which homosexual behaviour has not been previously reported. In 2018, the first report of sex between males was recorded. This suggests that homosexual activity is not a recent human construct, in cultural or even in evolutionary terms, but instead occurs along many branches on the tree of life.

Dolphins

Reports show that both female and male bottlenose dolphins engage in non-reproductive sexual activity without regard for biological sex, including being observed stimulating each other with their snouts. One pod of Amazon river dolphins was even spotted engaging in homosexual group sex.

In the bottlenose world, homosexual activity occurs with about the same frequency as heterosexual play. Male bottlenose dolphins are generally bisexual - but they do go through periods of being exclusively homosexual. In fact, male dolphin calves often form temporary sexual partnerships, which scientists believe help to establish lifelong bonds. 

Elephants

Both African and Asian elephants engage in homosexual intercourse and relationships. Reports show that female and male elephants alike are affectionate with their same-sex partners beyond sexual activity – doing things such as grooming, kissing, and intertwining their trunks – and that these relationships often last years.

Giraffes

Studies show that gay sex among giraffes makes up over 90% of all observed sexual activity in these animals, meaning giraffes engage in much more same-sex lovin’ than they do opposite-sex lovin.’

Male giraffes are especially interested in each other, and they don’t just get straight down to business! Male giraffes know how to flirt, first necking with each other - that is, gently rubbing their necks along the other's body, and this foreplay can last for many hours as theycourt and caress their potential partner.

Lions

Homosexuality is common among lions as well. Two to four males often form what is known as a coalition, where they work together to court female lions. They depend on each other to fend off other coalitions. To ensure loyalty, male lions strengthen their bonds by having sex with each other. Many researchers refer to this behaviour as your classical "bromance" rather than homosexual pairing.

Bisons

Homosexual activity between male bisons is more common than heterosexual copulation. That's because female bisons only mate with bulls about once a year. During mating season, males that get the urge engage in same-sex activities several times a day. And so, more than 50 percent of mounting in young bison males happens among the same gender.

Walrus

Male walruses only reach sexual maturity at the age of 4. Until then, they are almost exclusively gay. Once they've reached maturity, most males are bisexual and mate with females during breeding season - while having sex with other males the rest of the year. It's not just gay sex though - the males also embrace each other and sleep close to one another in water.

Sheep

Studies suggest that up to 8 percent of males in flocks of sheep prefer other males, even when fertile females are around. However, this only occurs among domestic sheep. Studies have found that these homosexual sheep have a different brain structure than their heterosexual counterparts and release less sex hormones.

In the past, homosexual behaviour was often ignored because it supposedly contradicted Darwin's theory of evolution. Scientists argued homosexuality was a sort of 'Darwinian paradox' because it involved sexual behaviour that was non-reproductive. Recent evidence however suggests homosexual behaviour could play important roles in reproduction and evolution.

So how far can we go in using animals to help us understand human homosexuality? Robin Dunbar is a professor of evolutionary psychology at the University of Liverpool, England. "The bottom line is that anything that happens in other primates, and particularly other apes, is likely to have strong evolutionary continuity with what happens in humans," he said.

Dunbar says the bonobo's use of homosexual activity for social bonding is a possible example, adding, "One of the main arguments for human homosexual behaviour is that it helps bond male groups together, particularly where a group of individuals are dependent on each other, as they might be in hunting or warfare."

For instance, the Spartans, in ancient Greece, encouraged homosexuality among their elite troops. "They had the not unreasonable belief that individuals would stick by and make all efforts to rescue other individuals if they had a lover relationship," Dunbar added.

There are many other theories about why homosexuality is important for reproduction and evolution in animals. One is the 'bisexual advantage' model where animals with a more fluid sexuality are more likely to reproduce. According to some scientists, bisexuality may be "an evolutionary optimum phenotype in many species, including humans."

Other models consider whether a gene is beneficial for a specific sex. For example, if the gene were 'feminizing' in the sense that it would lead to females having more offspring, so it would be passed on in spite of being disadvantageous for a male's own reproduction, i.e. being homosexual. Meanwhile, others posit that homosexuality could also play a role in evolution through co-parenting or helping to raise relatives' offspring. These explanations are not exclusive of one another, and it is likely that a combination of factors is important for the evolution of homosexuality within the animal kingdom.

Whatever the reason, it goes to show that, much like in humans, being LGBTQ+ is a completely natural occurrence, and if the monkeys, lions, beetles and dolphins can accept it as a natural and common part of life without any fuss, then surely, we can too.