Some problems of collection planning for great apes
The mission of the EAZA Great Ape TAG is to maintain self-sustaining populations of all the taxa of great ape to subspecific level where possible, and to encourage and promote their conservation in the wild. The role of zoo populations is primarily to act as ambassadors for educational purposes on the plight of apes in the wild, to further support for their conservation in the wild, and to serve as a research resource, the findings of which should be applied to improving their husbandry, welfare and in situ conservation. Zoo populations of great apes may also be vital for future reinforcement of wild populations and, therefore, should be managed to preserve maximum genetic diversity.
Deciding which taxa to manage to EEP, European studbook (ESB) or monitoring level, or which to label as ‘not recommended’, does not seem difficult at first glance. There is a limited number, all are endangered, charismatic and of high educational value, and there is enough space in EAZA zoos for those taxa that are present in viable population sizes. Still, there are some complications that make the TAG’s choices less easy than they appear at first glance. These are all related to taxonomical developments that resulted from the increased potential of DNA research and its interpretations.
After the difficult process of splitting the orang-utan population into the two island forms, we now realise that the Bornean species actually consists of several subspecies. This makes our population of Borneans a subspecific hybrid one. At this point it does not seem likely that one or more pure subspecies populations can be split off. The Sumatran species, for which subspecies have not been identified, is thus considered of higher conservation status, which may affect future choices.
In the population of western lowland gorillas, we cannot exclude the possibility that one or more founders from the Cross River subspecies have contributed.
Controversy still remains about the taxonomical status and number of different subspecies of chimpanzee. As a consequence there is only an EEP for the western subspecies so far. A strategy was developed to manage this EEP population within a much larger ESB population of generic chimpanzees.
Apart from the Bonobo EEP, all EEP population sizes exceed those needed for reaching the agreed genetic aims. Demand from EAZA members, the current situation, and the expected development of the populations were all taken into account in setting the target population sizes. It should also be kept in mind that in such long-living species, population developments are slow.
Demand from EAZA member institutions for great apes is developing. There is a tendency for zoos that build new and costly exhibits for great apes to expect what they believe to be the highest-profile species. Zoos that traditionally kept a varied collection of great apes tend to reduce the number of species and stop keeping what they believe to be the lowest-profile species. These tendencies do not always match the actual developments in the populations.
With the agreed aims set, EEPs have a basis for their management. Practice, of course, does not always follow the ideals, sometimes resulting in dilemmas, often involving animal welfare issues, which are often similar for all the great ape species. Some examples of these dilemmas follow.
Historically many great apes in captivity have been hand-reared, often to save babies whose mothers did not provide adequate care for them. It is understandable that the physical well-being of the young apes was the primary concern, and what better model was available than human babies? So these apes were generally reared in a human environment, wearing human baby clothes, drinking human baby milk and receiving love and affection from their human family members. It took quite some time to learn that this is not an ideal preparation for adult life in a social group of great apes. What to do, then? Leave the baby with the mother until it dies from lack of care, or is killed by other group members? Euthanize it, even though it is still in excellent health? In order to help zoos to make the best choices, the TAG created guidelines that allow for the best course of action to be found in each specific case. Although called Hand Rearing Guidelines for Great Apes, this document also describes what steps to take to avoid unnecessary hand-rearing.
Great apes are generally kept in family groups, so the founding generations count more females than males. The sex ratio at birth is quite different, though, 50:50 at best or even male-biased. This means that not all males can be placed in family groups when they grow up. This is a real problem for most programmes. There are several possible solutions, but some of them have their downsides too. One way of solving the sex ratio problems could possibly be to castrate young males at a very early age. 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.
Strangely enough, quite a number of zoos seem eager to castrate their chimp males, while most zoos hesitate to castrate their young gorilla males when they are asked to do so by the EEP coordinator. In both cases it is important to cooperate with the coordinators. A concern, of course, is which males to choose for castration. Genetically valuable individuals should not be picked: but genetic value can change over time.
Another concern is that with castrated males an unnatural element is introduced into the social structure. To what extent will this affect behaviour in the groups? Will the welfare of a castrated male benefit, because he can stay in a social group and is freed from the urge to strive for dominance? Or will his welfare suffer because his behaviour does not fit into the natural social structure and his physique and hormonal drive do not combine well with his innate behaviour?
There is simply not enough experience yet with all species to conclude that this is indeed a good option. We need to expand our experience and evaluate the results.
Researching elephant intelligence
Using a variety of tests, researchers from several different institutions are trying to find out just how intelligent elephants are. Time and again the researchers discover that we still know very little about elephants, but that they have capacities that had up till now only been seen in humans and primates. Elephants can’t see very well, but their hearing is exquisite. Tests were performed on elephants in the Amboseli National Park in Kenya. Using a contact sound (‘Here I am, where are you?’), a deep ruffle that can be heard over a great distance, it was tested how many contact sounds elephants are able to distinguish. Matriarchs, the female leaders of the herd, can distinguish at least a hundred different sounds, i.e. more than a hundred different elephants. The researchers compared this with a test in which a human participant had to distinguish a hundred different persons, placed behind a fence, on the basis of their voices.
Elephants in a Japanese zoo were tested on their numerical skills. Different numbers of objects were placed in buckets and the elephants had to indicate if there was a difference. Similar tests have been performed with children and various primates. Most people find it easier to distinguish one and two than five and six. But this was not the case for the elephants: they could distinguish five and six just as easily as one and two.
The elephants in Amboseli also seem to hear the difference between human languages. Several different languages are spoken in the region. The Maasai, a nomadic people, speak Maa. The Kamba, farmers, speak their own language. And there are often English-speaking tourists in the park. The elephants have most to fear from the Maasai, who sometimes retaliate when elephants kill their livestock. They have the least to fear from tourists, who mainly want to take photos. When a researcher’s assistant spoke Maa to the elephants, they became anxious. But when he spoke Swahili, peace returned and the animals continued eating. The language skill of the elephants has not yet been investigated further, but the researchers say it is definitely interesting.
Zoos prefer to keep beautiful parrots, but is less conservation the result?
Parrots are one of the most frequently kept and bred bird orders in captivity. Thus, they may be poached more than other birds, which in turn increases the potential importance of captive populations for rescue programmes managed by zoos and related institutions. Both captive breeding and poaching are selective and may be influenced by the attractiveness of particular species to humans. A group of researchers from the Czech Republic and Germany recently tested the hypothesis that the size of zoo populations is not determined only by conservation needs, but also by the perceived beauty of individual parrot species assessed by human observers (Frynta et al., 2010).
For the purpose of data collection, the researchers defined four sets of species (367 parrot species/subspecies, a reduced set of 40 parrots, 34 amazons, 17 macaws). They then asked 776 human respondents to evaluate pictures of the selected species according to perceived beauty, and they later analyzed the association with colour and morphological characters. Irrespective of the particular set of species, they found a good agreement among the respondents. The preferred species tended to be large, colourful, and long-tailed.
The researchers repeatedly confirmed a significant, positive association between the perceived beauty of parrot species and the sizes of their worldwide zoo populations. They used the population size as a simplified measure of ex situ conservation effort. Interestingly, the size of geographical distribution and body size both appeared to be significant predictors of zoo population size. In contrast, the effects of other explanatory variables, including IUCN listings, appeared insignificant. From their results the researchers suggest that zoos may preferentially keep beautiful parrots and pay less attention to conservation needs, although they do not imply an absence of beneficial rescue programmes managed by zoos. They also postulate an alternative interpretation of their data, i.e. that it could be evidence of the undesired effect of legal barriers preventing zoos from obtaining species worthy of conservation efforts.
The discussion by the researchers of the issues involved includes a fundamental aspect of which all modern-day zoos are acutely aware, not just for parrots but for all of their animals. The researchers concede that the absence of preference to keep only threatened species by zoos may be attributed to a dual function of these institutions, and does not necessarily mean the absence of conservation efforts and consequences. Thus they recognise that key functions of zoos are educational and cultural, and that successful exhibiting of not only rare, but also common, species improves public views towards animals and can increase support for conservation efforts with species in need.
The researchers suggest that their results corroborate the hypothesis that the fate of a species may be considerably affected by its core attractiveness to humans. Loro Parque (Tenerife, Spain) exhibits the largest diversity of parrots in any single zoological park worldwide, where the visitors can see both large, showy macaws and far less gaudy, small threatened parrot species. But an important element in the relative attractiveness of these different species is how they are presented to the visitors. And this applies equally in comparing the appeal of parrots to that of charismatic large mammals.
Zebra sharks in Europe
It is nearly three years since the start of the zebra shark studbook – the first official European studbook on a fish species. Zebra sharks (Stegostoma fasciatum) are tropical sharks that can reach up to 2.5 m in length. Not every aquarium has room for such a large species, but in the last two decades we have seen more and more big public aquariums built, which has enabled numbers of this attractive bottom-dwelling shark to increase dramatically. All zebra sharks in Europe originate from the wild, and the species is listed as Vulnerable on the IUCN Red List. It is now bred in captivity in six aquariums outside of Europe, and the common practice of sustainable collection management for mammal and bird species is now being extended towards aquarium management, too. Fish studbooks, such as that held for the zebra shark, may be a big help towards sustainable fish management.
Two studbooks have been published since the start of the programme. There are currently 25 participating aquariums, with 16.17 living sharks between them, and one of the first challenges was to gather all the species information from them all. We were delighted to see that there was so much interest within the aquarium community for the type of breeding programme we had established, and the population of zebra sharks grew quite rapidly. At the start of the studbook it was clear that only a few aquariums kept adult animals and even fewer kept pairs, but since the launch of the studbook more pairs have been formed, while other animals have now reached reproductive age.
In 2009 four aquariums had females that produced infertile eggs. Hagenbeck Zoo in Hamburg, Germany, had a female that produced infertile eggs, although they had no male. So it was decided, within the studbook, that an adult male from Burgers’ Zoo, Arnhem, should go on breeding loan to Hamburg. This is of course a very common occurrence for birds and mammals, but not within the aquarium community. Sharks are among the most important specimens in an aquarium collection, so it’s not so easy to arrange for one to leave the aquarium for a while, and transporting sharks of this size is not common practice either.
Then, in 2010, the first husbandry guidelines were published. The information was compiled from 24 aquariums in Europe, Asia and the U.S.A., both breeding and non-breeding institutions. As the studbook coordinator, I found it fantastic to see this free and open exchange of information – we can learn so much from each other’s practices and experiences. Interesting conclusions from the questionnaire we compiled were that three of the breeding facilities added much more vitamins A, B1, B2 and B6 to the sharks’ diet, while two others provided much more vitamins C, D3 and E. Whether it’s the combination of vitamins or just one vitamin in particular that is important for reproduction is as yet unknown. Adult animals should be kept in 200,000 litres or more to permit swimming space. Temperature may also affect the breeding results, and the strongest advice was to keep the animals above 25°C.
Last year a new zebra shark programme was approved by AZA, run by Lise Christopher from Shedd Aquarium, Chicago. Since a few U.S. aquariums are breeding this species, their studbook is at a different stage of management, and it has been decided that offspring from American colleagues are to be added into the European population. A number of fertile eggs will be sent over and hatched in Arnhem. The most important goal in the near future is reproduction within the European population and thus ensuring no animals will be taken from the wild.
Since the launch of the zebra shark programme, there are now more fish programmes being developed within EAZA. Besides the blue-spotted stingray ESB, which like the zebra shark one has existed since 2007, the EEP Committee approved the following new ‘fish’ studbooks in March 2010: sandbar shark, spotted eagle ray, blue-spotted maskray, short-snouted seahorse and long-snouted seahorse.
EAZA News – back issues wanted
I am hoping to obtain copies of all issues of EAZA News since the beginning. The numbers I would like to obtain are as follows: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17, 18, 20, 22, 23, 24, 25, 26, 27, 28, 30, 38 and 39. If you can help, please contact me at the address below in order to talk about prices and mailing costs.
Thank you very much in advance.
Mickaël Michault, Animal Keeper, Branféré Animal Park, 56190 Le Guerno, France.