European zoos castrating male gorillas for easier management

Update, 28 July 2014: Please sign this petition asking European zoos to stop castrating their gorillas.

What do you do with a male gorilla who is challenging the silverback in a zoo’s gorilla group? Do you do move him out to a “bachelor group” of all males, as we do in North America? Or do you castrate him, as is happening in European zoos? The answer, at first, seems clear: don’t castrate! Let the males develop into beautiful silverbacks! It tears at the heart.

To be fair, let’s look at the European position. The European Association of Zoos and Aquaria’s European Endangered Species Programme (EEP) is an intensive type of population management for a species kept in EAZA zoos. The gorilla EEP supports castration as a way to handle what are known as “surplus males,” the guys who can’t be kept in their maternal group because of the dynamics with the silverback.

“Hopefully these castrates can stay in their maternal group during their lives without big problems, or create fewer problems when growing up in a bachelor group,” is how Tom de Jongh explained it in the August 2010 EAZA publication Zooquaria.

The National Zoo moved Kojo and his brother into
their own "bachelor group" when tensions rose
between them and the silverback Baraka.
Baby sis Kibibi pictured here.

In North America, the Association of Zoos and Aquariums’ Species Survival Program (SSP) for gorillas does not condone castration as a management strategy. Instead, the SSP does tremendous work on strategies to create bachelor groups where the surplus males are put together – without a female to cause problems.

The SSP has had a great deal of success with this strategy, especially when following some specific guidelines regarding age of introductions and flexibility in management. AZA zoos manage 27 all-male groups and a recent a paper on the behavior of males in different gorilla SSP social groups (Stoinski, et al., 2013) shows that with proper management, all-male groups are a stable long-term strategy for housing males in zoos.

So why don’t the Europeans try the bachelor groups? They do. Over the last 20 years or so, they have established 19 bachelor groups. But they are evidently having trouble establishing more. “As we all know, good zoos willing to keep gorillas as they should do not grow on trees,” one British zoo official admitted in an email message.

I know that zoo people do not start out their day thinking, “I’ll think I’ll maim a perfectly healthy gorilla today.” I know they deal with tremendous problems, and sometimes there seems to be no good answers. If a gorilla is sent to a bachelor group, there is a risk that he may spend his life watching his back for attacks from the others. The cardiac stress and hypertension caused by the continual elevated cortisol levels under stress can be a very real concern. If he can’t fit in, he may end up as one more of those solitary gorillas living without any companionship whatsoever. If castration provides social stability and inner calm for the male who has nowhere else to live, and he can play with babies and be in a large group for a long time… then maybe the Europeans are right to consider the options.

If, if, if.. And yet…

We know castrations, especially those done at earlier ages, can cause behavioral deficiencies in apes, as an American ape expert explained to me. And the assumption that a castrate’s life may be longer and stress free is just a hypothesis without real data, unproven, since this would require hormone assays and cardiac monitoring over time. From a scientific perspective, we need facts about how well castration works to reduce aggression in gorilla families and bachelor groups. Unfortunately, getting those assays, monitoring, and behavioral data requires the castration of male gorillas.

The European zoos have put themselves into a Catch-22. Does castration hurt or help gorillas in the long run? They have to castrate the gorillas to find out. And the Europeans are castrating them without knowing if it helps or hurts the gorillas.

Ultimately then, it seems to come down to a question of values. I asked one former zookeeper what her thoughts were. “I am opposed to castrating any great ape unless his health is in danger,” she told me. “I dislike the concept for apes, their bodies are sacred, and as much as I can honor that, I will.”

On the Facebook page for Gorilla Haven - Gorilla Fans, Jane Dewar has posted the names of the ten males who have been castrated by European zoos thus far.

Kukuma #2089 - Belfast

Loango #1818 - Apenheul

D'jomo #1986 - Vallee des Singes

Zungu #1704 - Basel

Mosi #2040 - Gaiapark

Bembosi #2081 - Amsterdam

Shambe #2082 - Amsterdam

Mapenzi #2046 - Beauval

Mbula #2024 - Chessington

Mwana #2108 - Chessington

The EEP has recommended even more castrations – while their zoos continue to breed more gorillas. More male babies destined for the surgical knife in Europe, if the castration strategy remains in effect.

It would be nice to know, definitively, whether gorillas live longer lives with or without castration. It would be fantastic to know if they are happier. But we’ve been fighting against the use of chimpanzees in invasive research here in the States, so it’s not surprising that many American ape lovers rebel against the idea of castrating gorillas for research. The Europeans, though, would be the first to remind us that they aren’t castrating the gorillas for research. They are using a medical procedure to make it easier to control their populations. 

To me, castration is wrong. It is lazy. If the European zoos can’t manage their apes, they should: 1) stop making more of them; and 2) let us know which are the evidently dwindling “good zoos willing to keep gorillas.” Those are the zoos that the public should support. We already have the names of the zoos (see list above) that don’t deserve the support of people who respect apes for who they are… and for who they can – and should – become.