Plans to kill intelligent gorillas to solve zoo overcrowding have been slammed by campaigners who say they should be returned to the wild.
The Association of Zoos and Aquaria (Eaza) is said to be considering a cull due to the high number across Europe.
Eaza is responsible for the 463 great apes across its 69 locations.
But due to overpopulation, they are now looking for solutions to reduce the number of critically-endangered western lowland gorillas in their facilities.
One western lowland subject logged an IQ score between 70 and 90 – which isn’t far off the 85 to 115 logged by most humans.
Culling is not the only option being explored. Eaza is also considering castrating and housing adult males in isolation – methods that are currently in use.
A gorilla action plan seen by the Guardian, tells shareholders that culling is the “most appropriate tool” in biological terms.
They also realise the “emotional” nature of killing great apes and how it could enrage the public.
The document reads: “The main downside of this option is that it is controversial in many countries and in some illegal, in specific circumstances.
“Any discussion on culling can quickly become an emotional one because it is easy to empathise with gorillas.
“This carries a high risk that an emotional response by the public and/or zoo staff and keepers, catalysed by social media, inflicts damage to zoos and aquariums.”
Eaza’s 69 zoos are home to 212 male and 250 female gorillas, with another single animal of unknown sex.
When they reach a certain age, males can become violent when kept in all-male enclosures.
considerations. Campaigners are calling for the critically-endangered adult males to be rewilded
Campaigners are calling on the regulator to rewild the animals.
Conservationist Damian Aspinall says it’s a “sad day” for zoos when they have to consider culling.
His Aspinall Foundation has rewilded over 70 gorillas in the past 30 years, he says.
But the process is not simple, and gorillas need “pristine” habitats clear of humans or others of the species to be reintroduced safely.
This reduces the possibility of conflict and limits the likelihood of wiping out wild populations by passing on diseases picked up from humans.
Dr Ben Garrod, professor of evolutionary biology and science engagement at the University of East Anglia, told the Guardian culling can “serve a function”.
He adds that gorilla rewilding is tricky because they’re an “especially risky group” and there is a major lack of “pristine suitable habitat out there”.
Dr Garrod asked why zoos are allowed to breed the animal to the point that culling is even on the table.
“These are social, sentient and cultured animals. We do not have the right to treat them as surplus stock in this way.
“To breed animals like this without a sustainable and ethical outcome is reckless to say the least, and needs to be addressed.”
A spokesperson for Eaza admitted culling was an option being explored. But, they also said rewilding could be possible.
They said no gorillas have been culled to date, and they’re not recommending it at present.
This is not likely to change “over the short to medium term”, they add.
At present, Eaza castrates and isolates single male gorillas to control the population.
Castration is a “very common practice” used by vets to “ensure sustainable populations of animals and good social order between them”, a spokesperson said.
They added that housing single males alone is “not an ideal solution”, but the tactic has been used to maintain a “healthy population of gorillas”.