Captive Kangaroos Research Articles

Estimating age of wild eastern grey kangaroos through molar progression

Age is an essential attribute in studies of animal development, survival and reproduction. Here we evaluate the age estimation technique of molar progression devised for kangaroos in 1965. We used 71 wild eastern grey kangaroos (Macropus giganteus) that were first captured and aged as pouch young at Wilsons Promontory National Park, Victoria, and subsequently found dead between the ages of 1 and 14 years. We expected that the original equation, derived from captive kangaroos in Queensland, would not estimate age correctly due to differences in diet and/or clinal variation in skull morphology. We found no difference in rate of molar progression between males (n = 44) and females (n = 27). Our overall regression of age on molar index (MI) was log10 (age, days) = 0.284 (MI) + 2.511, r2 = 0.97. The slope of this equation was indistinguishable from that of the original one, meaning that molar progression in the wild was equivalent to that originally developed on captive kangaroos, despite likely differences in diet and morphology.

Toxoplasma gondii in four captive kangaroos (Macropus spp.) in China: Isolation of a strain of a new genotype from an eastern grey kangaroo (Macropus giganteus).

Marsupials are highly susceptible to Toxoplasma gondii infection. Here, we report T. gondii infection in four kangaroos from a zoo in China. Kangaroos were imported into China in 2000 and were since bred in zoo. In 2017–2018, four kangaroos died due to respiratory system disease or injury. The bodies were submitted to the laboratory to test for T. gondii infection. Antibodies to T. gondii were found in 75% (3/4) of the kangaroos via the modified agglutination test with the cut-off 1:25. Cysts were observed in the histopathological sections of tongue and diaphragm or squashes of fresh myocardium in two kangaroos. These cysts were confirmed as T. gondii by immunohistochemical staining and molecular biological analysis. One viable T. gondii strain was isolated from one kangaroo and designated as TgRooCHn1. DNA from T. gondii tachyzoites obtained from cell culture was characterized by 10 PCR-RFLP markers and the virulence genes ROP5 and ROP18. The genotype of this isolate did not match with any known genotypes; it was designated as ToxoDB#292. The virulence of TgRooCHn1 (104 tachyzoites) was non-lethal to mice, and it formed tissue cysts. To our knowledge, the present study is the first isolation of ToxoDB#292 strain from kangaroo. Improvemets for captive settings were initiated, including greater attention being paied to birds and stray cats, fed frozen meat for carnivores.

Association Between the Levels of Stress Markers and the Onset of Kangaroo Disease (Lumpy Jaw Disease) in Captive Kangaroos

Kangaroo disease (lumpy jaw disease; LJD) is a disease of the oral cavity in Macropodidae that may be caused by stress-related factors; however, detailed information about its pathogenesis is lacking. Therefore, in this study, we evaluated markers of stress in kangaroos with and without LJD to determine the factors that cause an LJD outbreak. We evaluated the oxidative stress value, antioxidant activity, and plasma cortisol concentration in blood samples. Additionally, we measured the cortisol concentration in saliva samples. The oxidative stress value and serum cortisol concentrations were statistically significantly different between the two groups, but the antioxidant activity and saliva cortisol concentrations did not differ significantly. Relatively large variations were observed for each value within individuals.

Molecular characterization and multi-locus genotypes of Enterocytozoon bieneusi from captive red kangaroos (Macropus Rufus) in Jiangsu province, China.

Enterocytozoon bieneusi is the most common pathogen of microsporidian species infecting humans worldwide. Although E. bieneusi has been found in a variety of animal hosts, information on the presence of E. bieneusi in captive kangaroos in China is limited. The present study was aimed at determining the occurrence and genetic diversity of E. bieneusi in captive kangaroos. A total of 61 fecal specimens (38 from red kangaroos and 23 from grey kangaroos) were collected from Nanjing Hongshan Forest Zoo and Hongshan Kangaroo Breeding Research Base, Jiangsu province, China. Using the nested PCR amplification ITS gene of rRNA of E. bieneusi, totally 23.0% (14/61) of tested samples were PCR-positive with three genotypes (i.e. one known genotype, CHK1, and two novel genotypes, CSK1 and CSK2). Multi-locus sequence typing using three microsatellites (MS1, MS3, and MS7) and one minisatellite (MS4) revealed one, five, two, and one types at these four loci, respectively. In phylogenetic analysis, the two genotypes, CHK1 and CSK1, were clustered into a new group of unknown zoonotic potential, and the novel genotype CSK2 was clustered into a separate clade with PtEb and PtEbIX. To date, this is the first report on the presence of E. bieneusi in captive red kangaroos in Jiangsu province, China. Furthermore, a high degree of genetic diversity was observed in the E. bieneusi genotype and seven MLGs (MLG1-7) were found in red kangaroos. Our findings suggest that infected kangaroo may act as potential reservoirs of E. bieneusi and be source to transmit infections to other animal.

Behavioural adjustments of wild-caught kangaroos to captivity

It is important to understand how wild-caught animals may respond to captivity, and whether their behaviours in captivity are reflective of their wild counterparts. We observed the behaviour of wild-caught western grey kangaroos (Macropus fuliginosus) and red kangaroos (Osphranter rufus; formerly M. rufus) that were transferred to a large naturally vegetated enclosure. Observations were made on the first day of captivity and again after 7–10 days, and were compared with the behaviour of free-living kangaroos at the same locality and over the same period. We quantified feeding, moving, grooming and non-alert behaviours. Of these, grooming was higher in captive kangaroos than in free-living animals on the first day of captivity only, and was no different to that of wild animal by 7–10 days’ captivity. Such self-directed behaviour may be indicative of heightened distress for kangaroos on the first day of captivity, but it may also be indicative of grooming to eliminate contamination of human smells or debris following capture by darting and recovery. Overall, our findings indicate that after a short period of captivity, wild-caught kangaroos adjust to a novel environment relatively quickly, and animals from each species showed behaviour patterns comparable with free-ranging counterparts within 7–10 days after capture and captivity.

Herbivore feeding preferences in captive and wild populations

AbstractInvestigations into the mechanisms underpinning plant selection by herbivores have often yielded conflicting results. Such inconsistency might stem from whether selection experiments are conducted with captive or wild populations, and upon the different measures of plant selection used to determine herbivore preference. Here we compared the feeding preferences of captive and wild kangaroos (Macropus fuliginosus) using a standard set of plant species (14 Hakea spp., Proteaceae) and several measures of herbivore selection to examine how environment influenced relative consumption. Three indices of herbivore consumption were measured: number of plants (NP), total shoot volume per plant (TV) and percentage available shoot volume (PV) consumed. NP and TV were closely correlated in the wild and captive populations and consistently correlated with six morphological and chemical plant attributes examined, the most notable being a strong negative correlation with shoot phenolic content. This uniformity suggests that plant selection by captive kangaroos is broadly consistent with that observed in field trials, and consequently that for macropods, at least, captive trials offer a valid way to determine the relative acceptability of different plant species. However, the fact that our third measure of herbivore selection PV was weakly correlated in captive and wild populations and showed no relationship with shoot phenolic content highlights the importance of which measure of plant selection is applied. We suggest that, while NP and TV are potentially confounded by plant size and availability, they offer the clearest insight into plant selection from the point of view of the herbivore, while PV is more suitable for plant‐centred studies.

A Retrospective Study of Disease in Captive Kangaroos from Oklahoma State University, 1995–2009

The antemortem biopsy records (5 cases) and necropsy records (34 cases) were reviewed from 39 kangaroo case submissions during a 14-year period to the Oklahoma State University and the Oklahoma Animal Disease Diagnostic Laboratory. The most common types of diseases in the kangaroos, based on necropsy examination, was disease of the alimentary tract (12 cases), pneumonia (6 cases), and disseminated toxoplasmosis (5 cases). The cause of disease was not determined in 6 case submissions. Based on histopathologic findings, clostridial enteritis/colitis was suspected in 2 kangaroos. Coccidian parasites were identified within histologic sections of the small intestine in 1 kangaroo. Pasteurella sp. (1 case) and Bacteroides sp. (1 case) were isolated from the lung in 2 cases of pneumonia. Most (77.3%) of disease in this study in the kangaroos with known ages occurred in animals older than 1 year. Two neoplasms were detected in the antemortem biopsy samples from 1 case.

Experimental reproduction of viral chorioretinitis in kangaroos.

To investigate whether preparations containing Wallal and/or Warrego viruses could cause disease when inoculated subcutaneously into captive kangaroos. Four groups of two kangaroos, seronegative to both Wallal and Warrego virus, were each inoculated with wild Wallal virus, cultured Wallal virus, wild Warrego virus, or wild Warrego virus followed by wild Wallal virus after 3 weeks. A single uninoculated animal served as a control. Animals were monitored weekly under anaesthesia, examined ophthalmoscopically (including fundic photography), and samples collected for haematological and serum biochemical analysis, virus isolation, PCR and serological examination for antibodies against Wallal and Warrego viruses. Animals inoculated with cultured Wallal virus were killed at week 10, and remaining kangaroos were reinoculated with cultured Wallal virus at week 12. Virus was isolated from the blood of two kangaroos 2 weeks after inoculation with Wallal virus preparations, and from a third kangaroo 2 weeks after reinoculation. By 3 weeks after inoculation, all kangaroos given Wallal virus preparations had seroconverted to Wallal virus and one had seroconverted to Warrego virus. Fundic changes were detected in the three viraemic kangaroos 4 or more weeks after inoculation, and lesions were present in the eye and brain typical of those seen in field cases of chorioretinitis. No other kangaroos had lesions. Wallal virus was identified by PCR and immunohistochemical analysis in the retina of one affected animal and orbivirus-like particles were seen by electron microscopy in the remains of retinal cells. The condition of chorioretinitis was reproduced in three of eight kangaroos by inoculation with preparations containing Wallal virus.

Validation of aging keys for eastern grey kangaroos, Macropus giganteus

Aging keys derived from captive grey kangaroos of known age were tested for their reliability in predicting the age of other captive animals of known age. Known ages were generally within the ranges of predicted ages. The aging keys were tested for consistency in age estimates derived from different body measurements. Although the age estimates for the additional captive animals were consistent, a sample of wild grey kangaroos appeared to have slightly different body proportions from those of the captive kangaroos.

Breeding Biology and Current Status of the Grey Kangaroo, Macropus Fulginosus Fulginosus, of Kangaroo Island, South Australia.

A distinct large dark brown kangaroo first attracted the attention of Europeans during the early exploration of Kangaroo I. in 1802-03. Although specimens were collected and the kangaroo ade- quately described, its subsequent taxonomic history was confused, and its origin long held to be Tasmania. This fallacy was not corrected until 1923-24. Subsequently the kangaroo has been re- cognized as a subspecies of the western grey kangaroo. Reproduction and growth of the young were examined in both wild and captive kangaroos. Males and females became sexually mature from age 20 months, the oestrous cycle was 34.6+ 3.2 (SD) days and the length of gestation 30.8 � 1.8 days. Births occurred on all months of the year but were more frequent in summer. The pouch life was just over 300 days, while loss of such young usually resulted in return to oestrus after an interval of 6.3 � 0.1 days. Disparity in sex ratio of the young was not significant. During their first year, young were measured each week. Growth curves are presented and linear or quadratic regressions fitted where applicable, together with 95% confidence limits.

Lumpy jaw in captive kangaroos

Lumpy jaw in captive kangaroos

COCCIDIA IN WILD POPULATIONS OF THE RED KANGAROO, MEGALEIA RUFA (DESMAREST), AND THE GREY KANGAROO, MACROPUS CANGURU (MUUELLER).

The incidence and prevalence of coccidia have been studied in populations of free-living red kangaroos, Megaleia rufa, and grey kangaroos, Macropus canguru, in four geographically distinct areas in Australia.Two new species of Eimeria—E. wilcanniensis and E. toganmainensis—are described from M. rufa, and five—E. cunnamullensis, E. gungahlinensis, E. purchasei, E. kogoni, and E. hestermani—from M. canguru.The incidence of coccidia ranged from 6 to 14% in populations of M. rufa and from 26 to 70% in M. canguru. The susceptibility of the animals to coccidia was analysed in relation to the tibia length. Red kangaroos with tibia approximately 360 mm. long and corresponding to an age of about 12 months were found to be most susceptible. No clinical cases of coccidiosis were seen in the field.Special thanks are due to the owners or managers of the properties on which the kangaroos were sampled; to members of the staff of the Regional Pastoral Laboratory ‘Gilruth Plains’ for their assistance in sampling, and to Messrs E. R. Hesterman, C. Kogon, and D. Purchase, who assisted in the field and the laboratory. Three species of Eimeria have been named after them in acknowledgement of their work. Messrs B. V. Fennessy and J. H. Calaby of this Division kindly read the manuscript.I wish to thank Dr G. B. Sharman for his permission to work with captive kangaroos in Canberra, and Mr E. Slater who took the photographs.