Australian Zoos Research Articles

Safety and immunogenicity of an adjuvanted recombinant spike protein-based severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine, SpikeVet™, in selected Carnivora, Primates and Artiodactyla in Australian zoos.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can infect a broad range of animal species and has been associated with severe disease in some taxa. Few studies have evaluated optimal strategies to mitigate the risk to susceptible zoo animals. This study evaluated the safety and immunogenicity of a protein-based veterinary SARS-CoV-2 vaccine (SpikeVet™) in zoo animals. Two to three doses of SpikeVet™ were administered intramuscularly or subcutaneously 3-4 weeks apart to 354 zoo animals representing 38 species. SpikeVet™ was very well tolerated across all species. Minor adverse effects were observed in 1.69% of animals vaccinated, or 1.04% of vaccine doses administered. Preliminary immunogenicity analyses in representative carnivores (meerkats, lions) and an artiodactylid (domestic goat) showed SpikeVet™-immunized animals developed serum antibodies able to neutralize a range of SARS-CoV-2 variants, including the vaccine-homologous Wuhan and Mu variants, as well as vaccine-heterologous Omicron BA.2 and XBB.1 strains. Prior to vaccination, all eight lions were seropositive for Wuhan strain by surrogate viral neutralization testing, suggesting past infection with SARS-CoV-2 or cross-reactive antibodies generated by another closely related coronavirus. These results from a range of zoo species support the ongoing development of SpikeVet™ as a safe and effective veterinary SARS-CoV-2 vaccine.

Geckos in zoos: A global approach on distribution patterns of threatened geckos (Gekkota) in zoological institutions

According to the One Plan Approach to Conservation, proposed by the IUCN SSC Conservation Planning Specialist Group (CPSG), there is, besides in situ conservation measures, also increased need for ex situ conservation breeding of threatened taxa. To gain a better overview of the current situation, we have compiled information from the zoo databases ZIMS (Zoological Information Management System) and ZTL (Zootierliste) on the husbandry of gecko species (suborder Gekkota) worldwide. Only 9.3 % (n = 201) of the 2151 currently recognized gecko species from seven families were kept according to ZIMS, of which about 20.4 % (n = 41) were classified as threatened. Most species were kept in European, North American and Australian zoos. Many of the species were kept outside the natural distributional range hotspots of geckos. However, institutions in Oceania kept mainly native geckos. The species richness of the natural distributional ranges of zoo-kept geckos was highest in Australia, Southeast Asia, Madagascar and lowest in South America. About 38.0 % (n = 25) of zoo-kept species with a successful breeding record were threatened, and most reproductive successes of threatened species have been recorded from only one institution per species. Although Gekkota is the most species-rich group among lizards (Sauria), they are still relatively poorly represented in zoological institutions, and most of the kept species are not threatened. Zoos inside and outside the distributional range can play a key role in conservation (breeding) programs, when they continue to provide their expertise and resources for the buildup of insurance colonies for threatened taxa. Preferably this is carried out in cooperation with experts and conservation centers from the species’ range countries and also in cooperation with Citizen Conservation programs.

Effects of the presence of zoo visitors on zoo-housed little penguins (Eudyptula minor)

ABSTRACT Little penguins (Eudyptula minor), or Kororā in Māori, show variation in their behavioural responses towards zoo visitors in Australian zoos. We experimentally examined the effects of visitor presence on the behaviour and stress physiology of little penguins at Wellington Zoo, New Zealand. The two treatments were: (1) Visitor presence – the exhibit was open to visitors; and (2) Visitor absence – the exhibit was closed to visitors. We found that when the exhibit was closed to visitors, the percentage of penguins observed close to the visitor viewing pier increased from about 1% to 9%, but there was little effect on other behaviours and faecal glucocorticoid metabolite concentrations. This result of increased avoidance of the visitor viewing pier when the exhibit was open to visitors suggests close visitor contact, particularly from above, may be fear-provoking for these penguins. We conclude that designing enclosures to allow close viewing proximity of visitors, such as visitors looming over the pool, may be futile in improving visitor experience, since this species of penguins is likely to avoid these types of viewing areas when visitors are present. Visitors positioned close to and above penguins may be particularly problematic since visitors in this position may be perceived as threatening.

Visitor Attitudes Toward Little Penguins (Eudyptula minor) at Two Australian Zoos.

This study identified and compared the attitudes of visitors toward zoo-housed little penguins, their enclosure and visitor experience that may influence the way visitors behave toward little penguins at two Australian zoos. Visitor attitudes were assessed using an anonymous questionnaire, targeting visitor beliefs, and experiences, where visitors were randomly approached at the penguin exhibit after they had finished viewing the penguins. Visitors were given two options to complete the questionnaire, on an iPad during their zoo visit or online (URL sent via email) after their zoo visit. A total of 638 participants (495 at Melbourne Zoo and 143 at Taronga Zoo) completed the questionnaire, 42% were completed onsite during their zoo visit and 58% were completed online after their zoo visit. Most participants were living in Australia, non-zoo members, female, previously or currently owned a pet, aged between 26 and 35 years and had a University degree. Results showed that the attitude dimensions of visitors were consistent between the two zoos which indicates that these measures of attitudes were stable over time and location. Overall, visitors at both zoos had positive attitudes toward little penguins, penguin welfare, the enclosure, and visitor experience. However, whether these positive attitudes and positive visitor experience influenced the way visitors behaved toward the penguins remains unclear. There were some differences in visitor attitudes toward the perceived “aggressiveness” and “timidness” of little penguins, “negative penguin welfare”, “experience with the penguins”, “learning”, “visual barriers” and the way visitors rated their overall experience at the penguin enclosure. While the reasons for the differences in visitor attitudes and visitor experience between the zoos were not clear, some factors such as penguin behavior and enclosure design, may have been attributable to these differences. Also, a relationship was found between visitor attitudes and how visitors rated the welfare of penguins, the enclosure and visitor experience at the enclosure; more positive visitor attitudes were associated with higher ratings of penguin welfare, the enclosure and visitor experience. The practical implications of these results for zoos is unclear because the differences in visitor attitudes were numerically small. This requires further comparisons between zoos or enclosures that are more markedly different than the penguin enclosures in the present study and further research on how visitors assess zoo animals, enclosures and visitor experience.

Koala retrovirus diversity, transmissibility, and disease associations

BackgroundKoalas are infected with the koala retrovirus (KoRV) that exists as exogenous or endogenous viruses. KoRV is genetically diverse with co-infection with up to ten envelope subtypes (A-J) possible; KoRV-A is the prototype endogenous form. KoRV-B, first found in a small number of koalas with an increased leukemia prevalence at one US zoo, has been associated with other cancers and increased chlamydial disease. To better understand the molecular epidemiology of KoRV variants and the effect of increased viral loads (VLs) on transmissibility and pathogenicity we developed subtype-specific quantitative PCR (qPCR) assays and tested blood and tissue samples from koalas at US zoos (n = 78), two Australian zoos (n = 27) and wild-caught (n = 21) in Australia. We analyzed PCR results with available clinical, demographic, and pedigree data.ResultsAll koalas were KoRV-A-infected. A small number of koalas (10.3%) at one US zoo were also infected with non-A subtypes, while a higher non-A subtype prevalence (59.3%) was found in koalas at Australian zoos. Wild koalas from one location were only infected with KoRV-A. We observed a significant association of infection and plasma VLs of non-A subtypes in koalas that died of leukemia/lymphoma and other neoplasias and report cancer diagnoses in KoRV-A-positive animals. Infection and VLs of non-A subtypes was not associated with age or sex. Transmission of non-A subtypes occurred from dam-to-offspring and likely following adult-to-adult contact, but associations with contact type were not evaluated. Brief antiretroviral treatment of one leukemic koala infected with high plasma levels of KoRV-A, -B, and -F did not affect VL or disease progression.ConclusionsOur results show a significant association of non-A KoRV infection and plasma VLs with leukemia and other cancers. Although we confirm dam-to-offspring transmission of these variants, we also show other routes are possible. Our validated qPCR assays will be useful to further understand KoRV epidemiology and its zoonotic transmission potential for humans exposed to koalas because KoRV can infect human cells.

A RETROSPECTIVE STUDY OF REPORTED DISORDERS OF THE ORAL CAVITY IN LARGE FELIDS IN AUSTRALIAN ZOOS.

Disorders of the oral cavity are conditions reported by veterinarians that impact the health and welfare of large felids in human care. There have been no studies documenting the prevalence of these conditions and species affected in Australian zoos. A review of the medical records of lions (Panthera leo), tigers (Panthera tigris), cheetahs (Acinonyx jubatus), jaguars (Puma onca), snow leopards (Panthera uncia), Persian leopards (Panthera pardus saxicolor), and cougars (Puma concolor) from 10 Australian zoos and an online survey of zoo professionals from Australian and New Zealand zoos was performed to determine the recorded prevalence of disorders of the oral cavity in these species. Preliminary assessments were also made to determine if there was an association between the occurrence of tooth fractures and diet, feeding practices, species, sex, and age of the animal. The study also examined associations of these conditions with behavior, such as fighting, and husbandry practices, such as the provision of enrichment items. The review found that tooth fractures were common in tigers and lions greater than 8 yr of age. Animal caregivers attributed this to animals chewing on large, hard pieces of bone in some instances, but this could not be verified. Instances of bones being lodged between canine teeth were observed and appeared to be related to the feeding of bones of inappropriate size. Based on these findings, it is recommended that guidelines for bone size fed be developed and that animals over the age of 8 yr receive regular dental examinations under general anesthesia.

Impacts of visitor number on Kangaroos housed in free-range exhibits.

Free range exhibits are becoming increasingly popular in zoos as a means to enhance interaction between visitors and animals. However very little research exists on the impacts of visitors on animal behaviour and stress in free range exhibits. We investigated the effects of visitor number on the behaviour and stress physiology of Kangaroo Island (KI) Kangaroos, Macropus fuliginosus fuliginosus, and Red Kangaroos, Macropus rufus, housed in two free range exhibits in Australian zoos. Behavioural observations were conducted on individual kangaroos at each site using instantaneous scan sampling to record activity (e.g., vigilance, foraging, resting) and distance from the visitor pathway. Individually identifiable faecal samples were collected at the end of each study day and analysed for faecal glucocorticoid metabolite (FGM) concentration. When visitor number increased, both KI Kangaroos and Red Kangaroos increased the time spent engaged in visitor-directed vigilance and KI Kangaroos also increased the time spent engaged in locomotion and decreased the time spent resting. There was no effect of visitor number on the distance kangaroos positioned themselves from the visitor pathway or FGM concentration in either species. While there are limitations in interpreting these results in terms of fear of visitors, there was no evidence of adverse effects animal welfare in these study groups based on avoidance behaviour or stress physiology under the range of visitor numbers that we studied.

Escaping captivity: The biological invasion risk from vertebrate species in zoos

Worldwide, invasive alien species increasingly contribute to environmental change and are a massive drain on social and economic resources. In Australia, the detection of new vertebrate incursions (i.e., alien species not currently established) has increased over the last decade. In other parts of the world, zoos have been identified as one of the influential pathways for the establishment of alien vertebrate species. We quantified the number of vertebrate species released (escaped and stolen) from Australian zoos between 1870 and 2010. The majority of reported releases (185 out of 230) have occurred since 1985. Most of the species (77.9%), which have escaped, or been stolen, from Australian zoos have only ever been released once. In sum, escapes were much more common (89%) than thefts. Compared to the other three vertebrate classes (amphibians, birds, mammals) reptiles experienced a significantly greater proportion of thefts than expected by chance. Almost half of all escapes (46%) were bird species. Birds also had the lowest retrieval rate, and therefore posed the greatest potential risk to establishment and subsequent invasion. We used phylogenetic logistic regression models to assess the association of evolutionary traits correlated with the propensity of a bird species for escaping. There was only weak evidence of phylogenetic signal (association among related species) in the tendency of a bird to escape. Bird species were significantly more likely to have escaped if their current total collection size was larger. There was no relationship between escape and the type of holding (aviary versus free-range/open-pond), or life history traits (adult body size and geographic breeding range size). Zoos are a prominent part of our culture and play a valuable role in education and conservation. Captive animals, including those in zoos, are subject to release, through both intentional and unintentional pathways, however, the establishment of alien species associated with Australian zoos is extremely low. We conclude that, in Australia, the risk of introduction by alien species from zoos is low, and substantially less than other ‘backyard’ and illegal sources of private species keeping and trade.

Evaluating physiological stress in Sumatran tigers (Panthera tigris ssp. sumatrae) managed in Australian zoos.

Glucocorticoid quantification using non-invasive methods provides a powerful tool for assessing the health and welfare of wildlife in zoo-based programmes. In this study, we provide baseline data on faecal-based glucocorticoid (cortisol) monitoring of Sumatran tigers (Panthera tigris ssp. sumatrae) managed at the Melbourne Zoo in Victoria, Australia. We sampled five tigers daily for 60 days. Faecal cortisol metabolites (FCMs) in tiger faecal extracts were quantified using enzyme immunoassays that were successfully validated using parallelism and accuracy recovery checks. Two female tigers had significantly higher mean FCM levels than the two males and another female, suggesting that females may have higher FCM levels. A significant elevation was noted in the FCM levels for one female 2 days after she was darted and anaesthetized; however, the FCM levels returned to baseline levels within 3 days after the event. Comparative analysis of FCM levels of tigers sampled at Melbourne Zoo with tigers sampled earlier at two other Australian Zoos (Dreamworld Themepark and Australia Zoo) showed that FCM levels varied between zoos. Differences in the enclosure characteristics, timing of sampling, size and composition of groupings and training procedures could all contribute to this variation. Overall, we recommend the use of non-invasive sampling for the assessment of adrenocortical activity of felids managed in zoos in Australia and internationally in order to improve the welfare of these charismatic big cats.

Measuring zoo visitor learning and understanding about orangutans: evaluation to enhance learning outcomes and to foster conservation action

Despite the endangered status of the orangutan, very little research has sought to understand what people know about this species or the conservation challenges they face. As zoos are well placed to influence such understandings, the present study sought to explore knowledge following a visit to orangutan exhibits at three Australian zoos (N = 240). Two learning assessments were utilised, capturing (1) self-reported learning and (2) understandings in relation to the information zoos prioritise for inclusion on exhibit signage. The relationship between the latter, attitudes toward orangutans and intentions for future conservation behaviour were also explored. Higher knowledge scores were significantly (indirectly) associated with intentions for future conservation behaviour through higher attitudes (indirect effect = 0.15, std. error = .05, z = 3.12, p < .01). In turn, the zoo visited, satisfaction with orangutan activity levels, having visited orangutan natural habitat, a zoo visit in the previous 12-months, and older age were all associated with higher knowledge scores (model R2 = 20.3). The importance of enhancing visitor understandings (e.g. through improved exhibit design and signage displays, and through encouraging repeat zoo visits) for conservation action is discussed.

DERMATOPHYTOSIS IN ZOO MACROPODS: A QUESTIONNAIRE STUDY

Limited published data are available on dermatophytosis in zoo macropods, despite anecdotal reports of disease occurrence and recurrent mob outbreaks. The aim of this questionnaire study was to analyze data from Australian and international zoos to evaluate estimated disease prevalence in zoos housing macropods, affected macropod species, causative organisms, predisposing factors, clinical presentations, diagnostics, treatments, and disease risk management. Two questionnaires (initial detailed and subsequent brief) were distributed via email to zoo veterinarians, with an estimated response rate of 23%. The overall estimated disease prevalence from responding zoos was 28%, with 73% of responding Australian zoos and 14% of responding non-Australian zoos reporting disease. The first cases of confirmed and suspected dermatophytosis in several macropod species and in association with Trichophyton verrucosum and Trichophyton mentagrophytes var. nodulare are reported, with young red kangaroos (Macropus rufus) appearing predisposed. Diagnosis was most commonly based on fungal culture or presumptively on typical clinical signs of minimally/nonpruritic alopecia, crusting, and scaling distributed most frequently on the tail, pinnae, and hind limbs. Both disease resolution without treatment and resolution after an average of 1 to 2 mo of treatment were reported.

Visitors or Visits? An Examination of Zoo Visitor Numbers Using the Case Study of Australia

Usually cited in reference to the potential reach of zoo education, one of the popular figures for global zoo visitation is that 600 million people visit zoos annually. However, this number needs clarification on two fronts. First, there are many zoo visitors who are not included in the calculation because they visited a zoo that was not included in the count. Second, it does not take into consideration the people visit either the same or different zoos more than once annually. Using data collected from several sources, including zoo visitors themselves, this article focuses on one country--Australia--that contributes 15.6 million to the visitation total, and contends that the correct number of unique annual zoo visitors to Australian zoos is likely to be between 8 and 10 million. However, rather than suggesting an overemphasis on the potential of zoos for educating visitors, having regular repeat visitors represents a distinct advantage for zoos, allowing for progressive education opportunities.

MORBILLIVIRUS INFECTION IN LIVE STRANDED, INJURED, TRAPPED, AND CAPTIVE CETACEANS IN SOUTHEASTERN QUEENSLAND AND NORTHERN NEW SOUTH WALES, AUSTRALIA

We report serologic evidence of cetacean morbillivirus (CMV) infection in five of eight cetacean species found live stranded, injured, or trapped along the coast of southeastern Queensland and northern New South Wales, Australia between December 2005 and January 2011. Antibody to CMV was detected in 13 of 27 (48%) wild cetaceans sampled. Antibody prevalence was significantly higher in clinically diseased (69%) compared to nondiseased (18%) animals (P=0.018). There was high antibody prevalence (83%, n=6) in melon-headed whales (Peponocephala electra). Two of 13 (15%) captive cetaceans sampled between November 2005 and January 2011 had CMV antibodies and, as infection was unlikely to have occurred while in captivity, CMV infection appears to have been present in Australian wild cetaceans since at least 1985. These results indicate that morbillivirus infection is occurring without widespread cetacean mortality in this region. However, as the deaths of two immature Australian offshore bottlenose dolphins (Tursiops truncatus) were attributed to CMV infection, morbillivirus infection should be included in the differential diagnosis of disease in cetaceans in Australia. Captive cetacean populations may be prone to significant mortality as a result of CMV introduction, so strict quarantine procedures should be enforced when injured or stranded cetaceans are hospitalized and rehabilitated at Australian zoos and marine parks.

Afternoon shedding of a new species ofIsospora(Apicomplexa) in the endangered Regent Honeyeater (Xanthomyza phrygia)

The Regent Honeyeater (Xanthomyza phyrigia) is an endangered Australian bird species. Breeding populations have been established at Australian zoos in support of re-introduction programmes. This species is the host of a new species of Isospora (Apicomplexa). Oocysts are spherical, 25·8 (22·5-28·75) by 23·8 (20-26·25) μm with a colourless to pale yellow smooth wall undergoing rapid exogenous sporulation, 90% sporulated oocysts in 8 h at 20°C. Each oocyst contains 1 polar granule. Sporocysts are ovoid, 18·67 (17-19) by 9·49 (9-10) μm with a flat Stieda body and spherical substieda body devoid of a hyaline body. The asexual stages and sexual phase is within the enterocytes of the duodenum and jejunum. Faeces collected in the morning (AM, n=84) and in the afternoon (PM, n=90) revealed significant diurnal periodicity in oocyst shedding; 21% (18 of 84) of the AM were positive with the mean of 499 oocysts.g-1 compared to the PM with 91% (82 of 90) bird faeces positive with the mean of 129 723 oocysts.g-1. Therefore, parasite checks for these birds should be carried out in the afternoon to obtain an accurate result. The ecological significance of the high parasite burden in captive birds requires further investigation and comparison to the wild counterparts.

Assessing chimpanzee personality and subjective well‐being in Japan

We tested whether the cultural background of raters influenced ratings of chimpanzee personality. Our study involved comparing personality and subjective well-being ratings of 146 chimpanzees in Japan that were housed in zoos, research institutes, and a retirement sanctuary to ratings of chimpanzees in US and Australian zoos. Personality ratings were made on a translated and expanded version of a questionnaire used to rate chimpanzees in the US and Australia. Subjective well-being ratings were made on a translated version of a questionnaire used to rate chimpanzees in the US and Australia. The mean interrater reliabilities of the 43 original adjectives did not markedly differ between the present sample and the original sample of 100 zoo chimpanzees in the US. Interrater reliabilities of these samples were highly correlated, suggesting that their rank order was preserved. Comparison of the factor structures for the Japanese sample and for the original sample of chimpanzees in US zoos indicated that the overall structure was replicated and that the Dominance, Extraversion, Conscientiousness, and Agreeableness domains clearly generalized. Consistent with earlier studies, older chimpanzees had higher Dominance and lower Extraversion and Openness scores. Correlations between the six domain scores and subjective well-being were comparable to those for chimpanzees housed in the US and Australia. These findings suggest that chimpanzee personality ratings are not affected by the culture of the raters.

The Occurrence and Ape‐to‐Ape Transmission of the Entodiniomorphid Ciliate Troglodytella abrassarti in Captive Gorillas

Entodiniomorphid ciliates are often present in the colons of wild apes. In captive apes the infection tends to gradually disappear, with the exception of Troglodytella abrassarti. We used fecal examinations to screen the gorillas (Gorilla gorilla gorilla) in European (Czech Republic, UK) and Australian Zoos to explore the ape-to-ape transmission pattern of T. abrassarti. Gorillas from two out of three European Zoos were positive for T. abrassarti, while gorillas from the Australian Zoo were negative. We documented a horizontal transmission of T. abrassarti to a non-infected adult gorilla introduced into a Troglodytella-positive group in the Prague Zoo and traced the origin of the ciliate infection to the Paignton Zoo (UK) using serial fecal examinations. During this study, two infant gorillas born in the Prague Zoo (CZ) first became positive for T. abrassarti at the age of 9 mo. Ciliate morphology and the sequencing of the small subunit rRNA gene and the internal transcribed spacer rDNA spacer region revealed that T. abrassarti affects both captive gorillas and chimpanzees. We conclude that zoo transport plays a major role in the distribution of T. abrassarti among captive gorillas.

Identifying Behaviors to Target During Zoo Visits

Abstract Although many zoos and zoo associations state the capability and importance of influencing the behavior of zoo visitors, the little research conducted to date gives limited support for these statements. Addressing this deficit involves more research, but zoos also need to design communication strategies with the specific purpose of influencing visitor behavior. However, it's important, before designing a communication campaign, that zoos identify which behaviors to target. As a first step toward doing this, five nominal group technique (NGT) sessions were conducted with general staff from three zoos in Australia, as well as an executive body overseeing three zoos and members of a volunteer group for an urban zoo. Following NGT protocol, desired on‐site and off‐site visitor behaviors were identified and their importance prioritized. The most prioritized behaviors are presented here. The discussion in this paper focuses on the efficacy of the NGT sessions, the need for further capacity‐building in Australian zoos, and proposals for some areas of future research.

Indigenous Wildlife Interpretation at Australian Zoos and Wildlife Parks

This article evaluates indigenous wildlife interpretation at captive wildlife attractions in Australia. The sites included 13 wildlife parks/sanctuaries or zoos, one aquarium, and three indigenous-owned emu or crocodile farms. Telephone interviews were conducted with 35 managers (9 indigenous) and 26 indigenous staff at wildlife attractions that included verbal or written indigenous interpretation of wildlife. The indigenous guides verbally presented both traditional uses and personal stories about Australian wildlife followed by Aboriginal "Dreaming" or creation stories about totemic animal species. Nonindigenous staff explained traditional indigenous uses of wildlife followed by biological facts and species information. According to staff, tourists benefit from the inclusion of indigenous content at captive wildlife attractions by giving additional value or worth to the experience, broadening their mind, dispelling myths, learning/education about indigenous cultures, novelty and excitement for visitors, increasing cultural awareness, and developing more positive attitudes towards indigenous people. Managers and staff support the employment of indigenous guides to provide interpretive tours and talks at captive wildlife attractions. Key issues for wildlife parks and zoos to develop and present indigenous cultural knowledge through wildlife interpretation are identified.

Prevalence and cause of stereotypic behaviour in common wombats ( Vombatus ursinus) residing in Australian zoos

Aspects of captive common wombat behaviour were collected through two research experiments to determine the prevalence and cause of stereotypic behaviour in this species. A total of 20 Australian zoos completed a behaviour-based survey, 80% of the total number invited to partake. Additionally, wombat-specific behaviours were video-recorded from 14 individual common wombats housed at three different Australian zoos. Results revealed that common wombats held in captivity are highly susceptible to the development of stereotypic behaviour. Eleven distinct forms of stereotypic behaviour were identified, with average time spent engaged in these behaviours ranging from 93 to 303 min (1.5–5.1 h) per day. Statistical analysis revealed that: (1) male wombats were more prone to stereotypic behaviour than females and (2) the amount of time a wombat spent feeding per day had an influence on stereotypic expression. Close examination of daily wombat behaviour indicated that these stereotypies arose as a result of restricted time allowances for performing food-related appetitive and consummatory actions.

Social, state-dependent and environmental modulation of faecal corticosteroid levels in free-ranging female spotted hyenas.

Little is known about to what extent the sensitivity of the hypothalamic-pituitary-adrenal (HPA) axis may be state dependent and vary in the same species between environments. Here we tested whether the faecal corticosteroid concentrations of matrilineal adult female spotted hyenas are influenced by social and reproductive status in adjacent ecosystems and whether they vary between periods with and without social stress. Females in the Serengeti National Park frequently become socially subordinate intruders in other hyena territories by undertaking long-distance foraging trips to migratory herds, whereas in the Ngorongoro Crater they usually forage inside their own small territories on resident prey. The faecal corticosteroid concentrations in Serengeti females were significantly higher than in Ngorongoro females. Energy expenditure by lactation is exceptionally high in spotted hyenas and this may be reflected in their corticosteroid levels. The faecal corticosteroid levels in both populations were higher in lactating than in non-lactating females. During periods of social stability, faecal corticosteroid concentrations increased in non-lactating females but not in lactating females as social status declined. Lactating Serengeti females had significantly higher faecal corticosteroid concentrations during periods with acute severe social stress than during periods without, indicating that the HPA axis is sensitive to social stimuli even in lactating females. So far few studies have used non-invasive monitoring methods for assessing social stress in freeranging animals. This study demonstrates for the first time, to the authors' knowledge, that corticosteroid concentrations may differ between periods with and without social stress for a free-ranging female mammal and that the modulating effect of social status may depend on reproductive status.