As I mentioned before, its a rather emotive issue. Here its been highlighted from a more general discussion, emphasising the interest/unease this issue creates. The interesting thing is castration has been practised on male chimps for a long time, particularly in the era of 'pet' or circus chimps to make them more tractable and manageable. In the Uk I think there's still at least one old castrated male at Twycross and maybe one or two at Monkeyworld too. It has largely died out now but never seemed to raise much comment-though in those days there was much less communication(no forums like this) perhaps it would arouse more if it was happening nowadays. But its not an issue for any chimps in zoo situations as adult male chimps naturally socialise together, whereas adult male gorillas normally don't. One other important difference seems to be a castrated male chimp still looks like a male Chimp whereas the castrated Gorilla male (Kukuma aged 19) at Belfast lacks the typical characteristics of an adult male. I still think more surplus male Gorillas will have to undergo this in the future though- the alternative may be putting them down.
I wonder what they would choose? I solitary life? A life spent with the stresses of being regually integrated into a new group? Casteration? It is definatley a option that would have to be considered by the ssp. As l cannot see them terminating male foetus or going to the expense of only fertalising females with female offspring.
I think only 1 & 3 are even relevant. Fully adult males are almost impossible to move into new groups, unless its one where they become the senior male among smaller younger males . (This is what happened with Mambi who was in the male group at Paignton, he was sent to be the oldest male in a group in France, and is now at Valencia) In some situations adult males that have lived together harmoniously will suddenly 'fall out' and start fighting badly and need to be separated. Once that happens separation usually is permanent. On the otherhand, some will live together okay e.g. the Loro Parc group and the 5 adult males in one group at Port Lympne. However, I'd say they 'tolerate' each other rather than anything else when kept like this.
Does anyone think it would be possible to design a unit where a number of silverbacks (say 3) could be kept separately, with perhaps occasional opportunities for a little visual and olfactory contact or some contact with younger males. Would the public accept it? Would the males be happier that way? Could they be moved into breeding groups if it became genetically desirable to do so? I'm thinking of circumstances like the fire at Philadelphia when their breeding animals were killed, which automatically made their surviving offspring at other zoos much more important. Alan
I think that would be very stressful for the animals; (limited) contact to other silverbacks is nothing positive for an adult male gorilla, but stressful and it may even shorten their life (heart problmes due to social stress). Plus the animals would be pretty bored. I`d really prefer to keep castrated males in the family groups where they can have friendly contact with females, or keeping groups of castrated males together, alone or with one uncastrated male as leader. I agree that the animals need to be very carefully selected to avoid the loss of genetic variability; in Europe, offspring from Matze/Rebecca or from the Jersey line with well-represented mothers (like the younger offspring of the Zurich group) would be candidates - they have many breeding siblings with many surviving offspring in different zoos. Bachelor groups with one silverback and serveral younger, "normal" males will certainly continue to play a very, very important role, because under this policy not that many males qualify for the radical method of castration.
Reading this...I think lucky Matze's son Richard is very happy he is already in Prague having his own group Well his second off spring is a male but I think he will avoid this considering that Prague gorillas are treated like celebrites. Their fans would get to know and apparently some of them would not understand.
What of splitting males off into smaller groups? Would it be possible say to have 1 male/2 females, and then rotate the groups on exhibit? I'm basing this solely on what I've seen in Orangutans...where two familites can be rotated between the large front exhibit, and the back holding areas. I'm not sure if this would hold true for gorillas (probably not), but it would be better than living a life of solitude/castration...right?
Unfortuantely, the sex ratio isn't always 50:50 in all species in captivity; in quite a bunch, more males than females are born. In a few others, like the Pygmy Hippo, it's the other way round. The reason(s) for this have not been clearly determined yet; it could be connected to the ample food offer in most zoos, but that's just a theory. Regarding Belfast's Kukuma: Similar as in pets and humans, the point in time of the castration and the thus affected level of testosterone might afflict the presentation of typical "male" features and behaviour. And castration isn't always that easy in all species-not just because of the anaesthesia risk, but also due to the testes being within the body cavity of the animal and not within an exterior scrotum (dolphins, elephants etc.), making it more tricky to get to them. There are various possibilities what could be done and is partly already done in regard to the control of the surplus male problem in gorillas: 1) Forming more zoo bachelor groups (limited) 2) Chemical or surgical castration of "unneeded" males (there is nothing as a "partial" castration, as the one testis left would compensate for the loss of the other) Disadvantage-once it's done, there's no coming back... 3) Artificial insemination (and yes, some institutes do have gorilla sperm samples stored) with previous selection of the sperm according to the haploid gonosomes (as Y-chromosome-carrying sperms are lighter than X-sperms, they can be seperated-a technique already used in human medicine, though illegal in several countries). The anaesthesia risk is indeed, as usual, always present-however, in more and more endangered species, AI is becoming a common practice-see Giant Panda. In terms of gorillas, there's the advantage of almost direct transfer of human medicine instruments and techniques-without having to build "special" equipment as in the case of other, more "exotic" species. At least in some cases, all-male gorilla bachelor groups have been observed in the wild. Therefore, the creation of such groups in captivity wouldn't mean an all too artificial sway away from natural gorilla social group structures. Disadvantage for the zoo: no cute babies... Reintroduction is not only limited to the reasons mentioned above, but also due to money(!), red tape and possibilty of disease transmission into the wild populations.
I guess that is pretty much the situation at Port Lympne nowadays. There are ten 'bachelor' males living in groups of 5, 1, 2 & 2. As you know the original big round house housing the 6 oldest silverbacks was originally designed with big sliding mesh divisions that could be opened or closed depending on if the males needed to be kept apart or not, rather like sections of a Pie. So far five of them have proved compatable and only the sixth(Timbou?) has to live permanently alone in his own section. I think in his case having contact with his erstwhile companions is probably a good thing and as he grew up with them, not at all stressful for him. He certainly looks very relaxed and uninterested in the others nearby. In the smaller 'Pavilion' at Port Lympne, the former group of four(which was formerly six before Boulas and Kishum went elsewhere) now seems to be permanently living in two pairs with visual/tactile contact if they want it. Again these males seem to show no interest in each other now but they had to be seperated for some reason. Some other zoos could perhaps organise something similar where solitary silverbacks could live within touch and sight of other gorillas. It would very much depend on the individual animals as to how well it would work, perhaps. Placing two stranger silverbacks near each other with visual contact can somewtimes result in very violent/hostile reactions. I suspect(though of course I cannot prove..) that at Twycross, silverback 'Mamfe's fatal heart attack in summer 2006 was induced by the several weeks of sudden activity/stress prompted by the appearance of another strange silverback (SamSam) whom he could see in the adjacent enclosure.
Trouble is most zoos like to exhibit one large group- silverback, females and young all together, and design their facilities accordingly. It would be perfectly feasible to do what you suggest if housing was designed for this. I believe many wild Lowland Gorilla groups are actually a lot smaller than typical captive ones, so a group with only a couple of females and youngsters might be just as natural too. The problem in zoos is that some males are not required for breeding at all because of the genetics. i.e. they come from very well-represented lines.
However, having a dominant male focus on just two females in captivity might result in quite some stress for all involved...
As far as I know, bachelor groups of Lowland Gorillas have NEVER been recorded in the wild. Research indicates males without harem groups live alone and tend to avoid contact with each other. The ONLY instance of a male group I know of was recorded by Diane Fossey in her study groups of Mountain Gorillas. I think it was Group 5 and comprised several males and a single old female (Effie). When Effie died the males continued to stay together, at least over a prolonged period. I believe the WHOLE concept of Gorillas living in bachelor/all male groups has stemmed from just that single (and possibly atypical) example. Regarding development after castration- Kukuma at Belfast was castrated as a youngster and appears not to have developed any of the secondary sexual characteristics typical of male gorillas. Loango also from Apenheul was done more recently at a similar early age so I'd expect a similar non-development for him also.
I can think of a number of groups past and present where there has initially been one male and two females to form a group. Mostly it works fine. Where it doesn't its usually because of behavioural problems of one or more individuals, rather than the actual male/female ratio.
Indeed, it has been reported in mountain gorillas so far; and in my opinion, this does "justify" the foundation of bachelor gorilla groups in captivity. If it works with mountain gorillas in the wild, why not with captive lowlands? The existing zoo bachelor groups seem to support this assumption. "Mostly" and "worked fine" are sometimes quite subjective parameters, as chronic stress is still hard to determine in wild animals; see "Wild Mammals in Captivity" on that, with an interesting example from LA Zoo. Some "fine" examples might have not been as harmonic as they appear-especially if You are not observing them intensely over a longer period of time.
To my mind one example(Fossey's group 5) of males associating together does not indicate a frequent or regular part of their behaviour. If bachelor groups of mountain gorillas were routinely seen by researchers studying wild groups, that's different, but they aren't. And if they have never been reported in wild Lowland Gorillas either- in fact quite the reverse in that males avoid each other, I don't think there's any evidence to back up the theory. Bachelor groups then become a product of captivity only. . As far as the captive groups are concerned, it works with younger males in the 'charge' of a single silverback. But with adult males its less successful because they fight- clearly they don't want to be together in that case..
Ha! Ha! Yes, I agree... And lets not only "fix" the castrators of gorillas; lets also "do" the clowns who ordered the castration of the only male hippo in New Zealand and the only male kudu in Australia (neither of which species is allowed importation any more.)
I am reminded of a comment by the owner and breeder of some lions who was being pressured by Animal Liberation to castrate his breeding males. " I refuse to order a procedure for my animals that I would not submit to myself" was his response.
This is a tangent- but the above mentality is also the reason why 9.6 million cats and dogs are euthanized in the States due to overbreeding. I realize the ethical debate that surrounds castration, but I do believe it has it's place in certain animals...a necessary evil unfortunately, until things get under control again. As to the gorilla castration...how about a vasectomy? Essentially the same as castration, only the side effects are less pronounced as the same hormones are still being produced. I also looked into chemical castration...it has it's negative side effects, but it is reversible. In either case, both methods used in humans, so it would fit nicely with the ethical concerns on this board.
What we are looking for is exactly a reduction in the hormones produced. To make the Silverback a less threating agressive animal. Intersting path though
