• Emily Prescott

The Sunday Times: Young male zoo gorillas face the chop

Eunuchs are easier to keep, say breeders in UK and Europe

Gernot tries to keep cool at London Zoo during the heatwave. He was fathered by Kumbuka, the zoo’s resident silverback REUTERS

In Africa they are the kings of the jungle, but male gorillas held in zoos in Britain and Europe may need a new title following proposals to castrate dozens of them to make them more manageable.

A 30-year project to build a 500-strong breeding population of endangered western lowland gorillas, involving 74 zoos — including London and Chessington — has been so successful that there are now too many males.

The scientists overseeing the breeding programme want to start castrating young males so that they develop more like “butch” females instead of turning into “silverbacks”, as mature males are known. Silverbacks are immensely strong and can be aggressive, making them hard to manage.

Now young gorillas such as Gernot, born three years ago at London Zoo, are on castration row, awaiting a decision as to whether they will be allowed to develop into fully equipped adult males.

“Gorillas produce equal numbers of male and female babies, but they live in harems of one male to two or three females, so we get surplus males,” said Neil Bemment, who oversees the European breeding programme. “As they grow, they start challenging their fathers and have to be kept separately or in bachelor groups, which causes a variety of management problems.”

Gorillas are the largest living primate and the most closely related to humans after chimps. Silverbacks can reach 200kg and lift up to 10 times their bodyweight, a strength that is thought to have evolved through the need to fight other males to win and retain a harem.

For Mbula and Mwana, young males living in Chessington Zoo, however, that will never happen. They are in a research group of 11 gorillas castrated over the past decade to see if “ungendered” animals are easier to manage. The results of that research, just published to coincide with the International Primatological Society’s biennial science conference, suggest castrated male gorillas could be kept successfully in the same enclosure as silverbacks and females. As a result, castration could be extended to more males.

“Seventy-five captive individuals (males and females of all ages), including 10 castrated and 10 intact juvenile/ adolescent males, from seven breeding groups were observed,” said the researchers in a paper. “Castrated males were found more frequently in the tolerance proximity of adults (male and female) than intact males.”

Castration — surgical removal of the testicles — is common in animal husbandry. Zoos use it too: many apparently female lions are actually castrated males. It is, however, more controversial when used on great apes because of their intelligence and closeness to humans and their highly evolved social structures.

For British zoos, which house 40 male and 60 female gorillas, it is a sensitive topic. At least one owner, the Aspinall Foundation, which runs Howletts Wild Animal Park and Port Lympne Reserve, both in Kent, and looks after almost 50 gorillas, opposes the idea. “We will not introduce castration for great apes,” said a spokeswoman.

“Where possible, we return gorillas born in Kent to protected areas of their [African] natural habitat.”

The breeding — and castration — programme is overseen by the European Association of Zoos and Aquaria (Eaza), which is also studying the caging of male gorillas in “bachelor groups”. Three UK zoos — Longleat, Paignton and Port Lympne — have tried this but David Williams-Mitchell, Eaza’s director of communications, said there was a drawback. “Every bachelor group [occupies a cage and] removes the opportunity to have a breeding group.”

Castration was an “ethical alternative”, he said: “Carried out at a young age, [it] prevents development of the full range of adult male characteristics and behaviours . . . research points to castrated animals continuing to live in their original family groups with no problems.”

Gorillas live for 40 to 50 years but Kukuma, the first European zoo gorilla to be castrated, died in Belfast Zoo aged 22 from anaemia. It is unknown if this was linked to his emasculation.

Gernot was fathered by Kumbuka, London’s resident silverback, and lives in a troop that includes four females. The zoo hopes he will be used for breeding, but his fate remains uncertain. “We will follow the breeding and management guidance for Gernot when he comes of age,” said a spokeswoman.

Read the full article: https://www.thetimes.co.uk/article/young-male-zoo-gorillas-face-the-chop-ttp8p5ktb

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