«Item type Thesis or dissertation Authors Davis, Nicolas Citation Davis, N., Schaffner, C. M., & Smith, T. E. (2005). Evidence that zoo visitors ...»
Wielebnowski, et al., 2002), imposed feeding regimes (Ames, 1993; Bassett & Buchanan-Smith, 2007; Bloomsmith & Lambeth, 1995), introductions to new environments and new group formations (Brent, Kessel, & Barrera, 1997; Doyle, Baker, & Cox, 2008; Soltis, Wegner, & Newman, 2003), regular veterinary procedures (Grandin, 2000; Laule, Bloomsmith, & Schapiro, 2003) and training (Bassett, Buchanan-Smith, McKinley, & Smith, 2003).
In practice it is still as difficult to assess the costs of captivity for animals as it is to assess its benefits to individuals, species and ecosystems (Mench & Kreger, 1996). In recent years there have been significant improvements in the care of animals in zoological parks, in particular in their physical comfort, nutrition and general health resulting in a great reduction in morbidity and mortality (Mench & Kreger, 1996). While it is fairly straightforward to meet the physical needs of most animals in zoological parks, there are concerns that they are still not meeting the more esoteric physiological or behavioural needs of a wide variety of rare and endangered animals (Mench & Kreger, 1996). It is also possible that some species requirements just cannot be met adequately in captivity and therefore are not suitable for life in captivity (Robinson, 1998).
Maintaining the behavioural diversity of a species, which includes a full repertoire of natural behaviours, has important conservational significance (Markowitz, 1997). Ex-situ breeding programmes in zoological parks have been successful in the conservation of some endangered species through reintroduction programmes (Kleiman, 1996; WAZA, 2005), although they have not been without their difficulties (Beck, et al., 1991; Kleiman, 1996). Released zoo bred animals are slow to adapt to their natural environment, which is attributed to the safe and controlled environment the animals were reared in which does not sufficiently prepare them for the complexity of the wild (Kleiman, 1996). Real preparation for reintroduction should include exposing animals to shortages of food, parasites and disease, the threat of predation and adverse weather conditions, which to many are seen as unacceptable and even against animal welfare legislation (Beck, 1991;
Veasey, et al., 1996b). Although species dependent, any reintroduction program requires an amount of pre-release conditioning, which for some species can be lengthy and expensive (Kleiman, Beck, Dietz, & Dietz, 1991). This has led to the argument that the high costs of reintroductions means that realistically, the limited resources available to the zoo community are best served by providing financial support for in-situ conservation programmes (Hutchins & Conway, 1995; Kleiman, 1996). Reintroduction programmes are also rare and of the 418 endangered species mentioned in zoo Action Plans, only 19 have reintroduction plans (Barathay & Hardouin-Fugier, 2002). Providing a more complex, enriched environment, even without exposure to more naturalistic stressors can improve the abilities of animals to eventually adapt to their natural habitat (Robinson, 1998).
1.5.1 Evaluation of welfare in zoos A scientific approach should be taken by zoological parks in the assessment and evaluation of their animals, and although the environment offers different challenges, the techniques successfully used in other captive settings should be adopted (Hill & Broom, 2009; Robinson, 1998). Although the evaluation of animal welfare is difficult it is generally recognised that a multi disciplinary approach is the best approach, including behavioural, physiological and psychological measures (Dawkins, 2004).
Behavioural studies have been highlighted as a useful method in assessing the welfare of animals in zoos, either through the presence of abnormal behaviours, stereotypies, or simply by comparison with the behaviour of conspecifics in the wild (Robinson, 1998). The use of cross-institutional behavioural studies has provided a means of increasing sample sizes to improve statistical reliability of zoo studies (Shepherdson, et al., 2004). The use of keeper surveys has also been an effective means of collecting data from large number of institutions (Hosey & Skyner, 2007;
Inglett, French, Simmons, & Vires, 1989; Wielebnowski, 1999). Such studies have proved effective in revealing specific environmental effects on zoo animal behaviour, reproduction and welfare (Mellen, 1994).
One approach to welfare promotion requires animals in zoological parks be given the opportunity to behave as they would in the wild (Chamove & Anderson, 1989; Thorpe, 1967). This would require information on the behaviours of wild conspecifics, in order to take account of specific behaviours they may be highly motivated to perform. Time budgets of wild behaviour can also be a good guide as to which behaviours should be encouraged, although there may be difficulties in their interpretation (Veasey, et al., 1996a, 1996b). Knowledge about the life history of species is also vital because it informs the design of housing and social environments. Animals have been categorised either as specialists that have evolved to exploit a specific niche or lifestyle, or generalists that are highly investigative and opportunistic and spend much of their time on the move (Morris, 1968). Although the dichotomy is an oversimplification, it can be a useful concept as it can be linked to an animal’s natural ecology. A specialist has specific needs and if these are provided then the animal can cope well within captivity. For example, specialists include grazing or browsing herbivores that spend most of their time eating vegetation, or sloths (sub order Folivora) and koalas (Phascolarctos cinereus) with highly specialised diets (Robinson, 1998). Generalists however need to be given a stimulating environment that promotes their natural tendencies for exploration and curiosity, and includes the canines, mustelids and primates (Robinson, 1998).
Generalists also tend to be omnivorous which suggest numerous and varied foraging techniques should be replicated in zoological parks.
The presence of stereotypies has been proposed as a useful indicator of poor welfare (Broom & Johnson, 1993) and increasing levels of stereotyping indicate a decreasing level of welfare (Dawkins, 1990). Reducing stereotypies has been identified as important in zoological parks and is one of the main reasons for their practice of environmental enrichment (Shepherdson, Mellen, & Hutchins, 1998;
Young, 2003). However, the mechanisms that underlie stereotypies are complex and although their presence should be seen as a warning of potential welfare issues they should never be used as a sole indicator of poor welfare for an animal (G. Mason & Latham, 2004).
A combined approach using cross-institutional behavioural observations with non invasive physiological measures could provide an insight into the complex relationship between stress and environmental variables of a zoo environment (Shepherdson, et al., 2004). Any cross-institutional assessment studies should take account of various potentially confounding factors which may affect results (Mellen, 1994). These include variations in enclosure size and complexity (Carlstead, Fraser, Bennett, & Kleiman, 1999; Van Keulen-Kromhout, 1978); management routines (Bassett & Buchanan-Smith, 2007); and breeding and seasonal variation of behaviour patterns (Bassett & Buchanan-Smith, 2007; Carlstead & Seidensticker, 1991).
Although the interpretation of cortisol studies are not without their difficulties with individual, age, sex and enclosure variation (Wielebnowski, 2003; Wielebnowski, et al., 2002), overall these studies indicate that non invasive monitoring of cortisol has enormous potential for investigating how management and behavioural problems are related to animal wellbeing. If conducted under the right experimental conditions, this could allow researchers and managers to identify problem areas of zoo management and evaluate the efficacy of strategies designed to promote animal welfare and increased reproductive success.
Although a better understanding of the requirements of exotic species kept in zoological parks has led to an improvement in their welfare in recent years (Mench & Kreger, 1996), there is still relatively little known regarding their specific needs and requirements (Hill & Broom, 2009; Robinson, 1998). For the studies that have been carried out to date, there has been a strong bias towards mammals, and in particular primates (Melfi, 2005).
1.6 Primates in zoological parks
Primates are highly intelligent sentient beings that display a complex behavioural repertoire and require a stimulating environment (McCann, et al., 2007).
This cognitive sophistication makes primates particularly susceptible to psychological stress arising from a variety of factors, not only through actual stressors but also in the anticipation of stress (Sapolsky, 2003, 2004). Primates also live in a variety of social systems, ranging from solitary, to pair living to multi-male / multi-female groups (Fuentes, 2007; Kappeler & van Schaik, 2002) and their social relationships within them are critically important (van Schaik & Aureli, 2000). When in captivity it is therefore essential that the appropriate conditions that satisfy their species-specific behavioural and social needs are met to ensure their wellbeing. For example, the separation of an individual that would naturally live solitarily is less of a welfare concern than the separation of an individual that is normally pair or group living, where a significant behavioural or physiological stress response is likely (Honess & Marin, 2006a).
Although the zoo environment has a number of environmental stimuli which have been identified as potential stressors, primates can be very adaptable and flexible (P. C. Lee, 1991) and living within a zoo environment should be within their range of adaptability (Poole, 1991). There can even be long term benefits of occasional and short-term stressors, particularly in early life, such as an increase in vigilance and an increase in the number of natural behavioural patterns (Chamove & Moodie, 1990). In zoological parks many aspects of an animal’s life history, such as feeding and reproduction, are beyond the control of the animals and are managed by humans (Hosey, 2008). Being confined can also reduce the ability of an individual to respond to aversive situations with appropriate escape or avoidance responses, which for social primates in particular, can be significant. These stressors can be in the form of proximity to predators, competing conspecifics, unfamiliar sounds, keeper interactions and perhaps one of the most prominent features, the presence of visitors (Carlstead & Shepherdson, 2000; Hosey, 2005).
There is evidence that some primates find life in zoological parks difficult with the performance of a variety of abnormal behaviours being reported and their causes needed to be identified and investigated (Hosey, 2005). It is essential that modern zoological parks can provide a suitable environment that a primate is able to adapt to. This is, however, not straightforward as there can be great variability in behaviour even within species to a range of captive environments. Comprehensive studies comparing the behaviour of different species in different captive and noncaptive environments are needed in order to identify the animals’ requirements. This includes how the different variables within a zoo environment, such as management, enclosure design and visitor presence interact with one another (Hosey, 2005).
1.6.1 Spider monkeys Spider monkeys’ social organisation is relatively unusual compared to most other mammals and primate species (Aureli & Schaffner, 2008), and this can potentially have an impact on their requirements for life in captivity. Although they live in multi-male/multi-female communities, a feature of many primate social groupings (Campbell et al., 2008), their communities are characterised by a high fission-fusion dynamic in which subgroup size varies due to the availability of and competition for resources (Kummer, 1971b). They spread out to forage in small subgroups or even alone in a flexible response that is dependent on the availability of food (Aureli & Schaffner, 2008; Aureli, et al., 2008). The constraints of captivity severely restrict opportunities for these fission-fusion events, but how this affects their social relationships within captive settings is not well understood and requires further investigation.
Living with high fission-fusion dynamics appears to reduce the need for the clear cut dominance hierarchies in females that are prominent in many primate species (Aureli & Schaffner, 2008). Female-female relationships in spider monkeys are generally low in value (Slater, Schaffner, & Aureli, 2009; van Schaik & Aureli, 2000), as females spend less time with other group members than males do and females disperse from their natal group on maturation (Di Fiore & Campbell, 2007).
In contrast, male-male relationships are generally strong, and with the relative lack of predation pressure they form coalitions in order to protect their territories and protect their females and food resources from surrounding communities (Aureli & Schaffner, 2008), although these relationships can be variable and can have high risks for maturing males (Vick, 2008). These features of spider monkey social life provide important considerations for how they are managed in captive settings.
1.7 Thesis outline