Pertinax has sugested that Belfast has experiance with this. Any other views ideas?? Yes it's a touchy subject for MEN!!! Also not a ideal situation, seems to work very well for dogs and horses.
In this matter I am not comfy with the management decision to castrate young male gorillas. I think it is rather a crude measure and ignores the very fact that we are always dealing with small population biology in captivity. Another aspect here is animal welfare ... which I do think is not helped by full castration depriving the young male gorillas of a social/reproductive replication of their natural life cycle (which I feel is the image serious zoos should look for) in a zoo environment. I would have thought that creating bachelor groups of (young) male gorillas was a real treasure trove find ... management-wise. To simply castrate (a) young male(s) to me fails miserably in the management and husbandry stakes. I wish/hope for some gorilla keepers on this forum who would be prepared to give their views from "close range" ...........
Actually I think castration of young, genetic overrepresented males will become necessary and I think that`s a better solution then euthanasation or keeping silverbacks all alone in crappy enclosures for all their life. Bachelor groups of adult (uncastrated) males usually don`t work long-term, unfortunately - look at Paignton, it works well there because they have only one adult male and when the younger ones mature and start to make trouble, they take them out of the group. But that`s not the solution, this way each bachelor group only provides a home for one silverback, and that`s not enough to solve housing problems in the future. Some silverbacks can be kept together in long-term (see Loropark Teneriffe), but it`s unpredictable and a big number of them will just make too much trouble. In the years to come, the number of silverbacks that need placement will overgrow the availible space, unless you believe it`s acceptable to keep gorillas in sleeping dens behind the scenes permanently. I think castration needs to be carried out only as last resort and only when a young male has really plenty of relatives, for example the 2 youngest males born in Frankfurt Zoo (Matze x Rebecca) and Zurich (N`Gola x Mamitu/Nache) are candidates. It`s not ideal, but I just don`t see a way out. These males will never get a group anyway because their bloodlines are so overrepresented, so they are not deprived of the rich social life of a group leader.
Its a touchy issue- are you depriving these near-human primates of an important part of their existence etc? As far as 'Kukuma' is concerned, he's 19 years old. It was originally done as an experiment ( presumably as a possible way of keeping surplus males in the future) and has actually worked fine, but it hasn't been repeated with any other males that I know of, at least in Europe. Yassa is correct in forecasting the outcome for excessive numbers of Silverbacks in the future. As adults some of them prove incompatable in male group situations which means they will have to live alone. There is already a lot of juggling around necesary to prevent the existing male groups having incompatable animals. Port Lympne and Loro Park both have groups of silverbacks but Port Lympne at least, also have other males that won't tolerate living together anymore. If there is no other choice, is it better for them to be deprived of their 'maleness' but be able to live socially, or be 'male' and forced to live in isolation? A minority of Chimpanzee males have been castrated fairly routinely over many decades (probably to render them harmless for training etc) without seeming to arouse much comment.
i know its a bit idealist, but couldn't these young males be introduced to the wild much like what the aspinal parks are doing, that way they would be spreading their perhaps over-represented captive lines into the wild adding new genes to the wild population. i realise this couldn't happen with all the males but its still a possibility.
to do this, they may need to take them away from mothers at early age to beable to teach them how to survive, so i dont think its a realistic option.
It might be possible with a few. Too many could affect the sex ratio in the release areas in later years. Also there are have been problems with some released males travelling away from the introduction areas and seeking out people by entering villages. I think several of the males from the Aspinall introductions have ended up being kept on an artificial 'island' of jungle, for their own and humans' safety- this part has not really been a success.
A good point. And males with poor social rearing are the ones that don't integrate easily in the wild, leave the groups and then enter villages and end up having to re-enter captivity or semi- captivity. All the Aspinall intros have involved 'orphans' and some of the males from these have later proved not to be good release subjects(see above)
I agree with Pertinax that release is no solution for more then a few males, having too many males in a wild population will result in too many violent encounters between family groups and lone silverback with the risk of injured adults and killed infants. Apart from that, responsable release of great apes is a huge undertaking, the animals need to be prepared and gradually introduced to their new life and need to be monitored to make sure they adapt well, that would take many years and cost huge amounts of money. I think the EEP needs solutions within Europe. A year or 2 ago, young Loango/formerly Apenheul was castrated and sent to Gaiapark, in the hope that he will be able to stay in the family group permanently. Given that Apenheul is the EEp coordinator, I think we`ll see more castrations in the future.
I didn't know about Loango. I think Kukuma could stay in Belfast's group forever so imagine that Loango will be similar. Like you, I can foresee this being increasingly used with the most over-represented young males produced. I don't think reintroduction schemes come within the remit of most zoos- other than the Aspinall Parks, so spare young males will still need to be housed somehow.
Very interesting discussion above. It has bearing on so many other species, since the birth ratio is 50/50. What to to do with the male lions, elephants etc? Not wanting to "kidnap" this thread, I would still be interested in further discussion on this matter - i.e. what to do with all the other species.
Hi matey, interesting question as it would seem a stupid thing to do! In the early 80"s l challenged the Bristol Zoo. As to why they would put there female gorillas onto a contraceptive! Then l was told. 1/ There was a shortage of suitable zoo's with enclosures that were adequate to house more gorillas. 2/ that they did not want some of the females mating with a close relative. 3/ There were too many male gorillas being born and that they were a problem when mature. As they would then require there own group or they would live in isolation. Something a highly intelligent sociable animal is not meant to do!! Nothing has changed in 25 years! What has evolved from the experience of Atlanta zoo and Howlettes. Is that male gorillas will live together for periods of time. Just not indefinatley, and often for short periods of 1-2 years. Also it is a huge problem when the male reaches sexual maturity and becomes a silverback. To move a Silverback gorilla from 1 group to another is a very difficult procedure given there highly evolved social structure.Apenhaul zoo in the Netherlands has spent at least 9 months gradually introducing there new silverback to the group. To move a Silverback from a 1 all male group to another all male group. Does not always work with success at all and can be very expensive and time consuming. The most successful arrangement to date is at Atlanta where the males were put together at a very young age and have grown up together. Atlanta zoo was very sure that the blood line of these gorillas was already very exposed in the captive population of Gorillas specifically North America. So in 2008 we have a surplus of male gorillas in captivity. Exactly what Bristol said would happen when l spoke with them. It's only going to get worse. I would say in 5-10 years time the problem will be huge. The castration of a gorilla seems like a feasible option to me. Certainly not what l would suggest in a perfect world but this is not a perfect world! The only experience l have with an animal that has been castrated is. Horses and dogs which l have had most of my life. They seem to adjust well. PS your picture are great!
Hypothetical situation (or real one?) Does anyone know if there is a gorilla semen bank somewhere? I'm pretty sure some zoos do it for their critically endangered animals where they can't ship the individual to other zoos to breed. So hypothetically- if there was a gorilla semen bank...we could castrate them without fear of losing their lineages....?
I don`t think there is a gorilla semen bank and even if it were, no, we couldn`t castrate them without fear of loosing their genes. A.I. doesn`t work with gorillas, only one infant has ever been archieved by A.I. and that was Ya Kwanza, born in Melbourne, about 25 years ago. It never worked again. even if the technique would improve, I don`t think A.I. will ever be a replacement for natural mating, because it will require to knock the female down. That`s very risky and should be done only in potentionally life-threatening situations. Having too many of a critically endangered species is nothing new and not unusual in zoos - critically endangered in the wild doesn`t mean there`s unlimited space in zoos. For a critically endangered species, it may take longer until all places are full, but if a species is reproducing well, that day will come. It`s just a matter of time until some sort of population control will be necessary. The demand for female gorillas will probably continue for a number of years, but due to their harem-lifestyle, there are less places for males, while the sex ratio at birth is 50%. In the wild, male gorillas face a higher mortality because life as a solitary silverback who is actively searching for (violent) encounters with family leaders to steal females is dangerous.
"Take your filthy paws off me, you damned ape!" So said Charlton Heston in The Planet Of The Apes when he learned that he was about to be castrated. Now, this is a switch! Although it's a legitimate tool for a difficult situation, I can't help feeling uneasy about it, particularly with a species so close to our own.
Well done Yassa- you have outlined the overall problem very succinctly(as per usual...) The requirements for captive group life mean that until a way is developed of artificially skewing the sex ratio of infants produced in zoos towards females, then there will a continuing male surplus. Artificial conditions sometime require artificial controls too, and castration may well be the only real option once all the places in male groups are filled and noone else wants to set up any more new ones (and they don't fully solve the problem with adult males anyway) I must say its not one I'm too happy with either as if Belfast 'kukuma' is typical, a castrated male is a rather sorry-looking creature not at all like a normal male but it seems to work well as far as group life is concerned, and that overall will prove the most important thing.
