The extent and causes of koala population declines are reported for koalas of southeast Queensland, but less is known about the trajectories of populations in other regions of the state. We describe the koala population of the Clarke Connors Range in central Queensland and contrast elements of their distribution, health and genetics with information from two other study sites in Queensland. Koalas were found across the study area, were mostly located in Eucalyptus drepanophylla or E. tereticornis and had wide variability in ranging movements (2.4–2246 ha). Approximately 40% of females carried young in spring and 3 of 29 koalas sampled returned PCR positive chlamydial swabs (all urogenital). We postulate that sympathetic land management approaches may have enhanced habitat occupancy across some areas of the Clarke Connors Range and concur with anecdotal reports that this is a significant population of koalas in Queensland and potentially one of national importance.

Free-ranging koalas generally feed at night; however, captive koalas are usually fed during the day in order to encourage activity for display purposes. We studied the temporal effect of feeding on body temperature of captive koalas in Queensland, to determine whether nocturnal feeding may be beneficial for koalas in warmer climates. Six adult koalas were implanted with thermal transmitters and data loggers, waxed together as a single package, to record internal body temperature. Koalas were exposed to two treatments: koalas were fed in the morning (between 0730 and 0830 hours) during the AM treatment or late afternoon (between 1700 and 1800 hours) for the PM treatment. The body temperature of koalas fed in the mornings was on average 0.5°C higher at its peak (P ≤ 0.01) when compared to koalas fed in the evening. Furthermore, the body temperature maxima of morning-fed koalas was reached ~2 h earlier in the afternoon, compared with those fed in the evening. There was no significant difference between behaviours associated with the two feeding regimes: inactivity (P = 0.840), feeding (P = 0.472) and activity (P = 0.634). We postulate that nocturnal feeding by koalas may be an adaptive mechanism that reduces diurnal heat load during times of high environmental temperatures.

The distribution of the koala (Phascolarctos cinereus) in Queensland is predicted to contract as a result of climate change, driven by the frequency, intensity and duration of heatwaves and drought. However, little is known about the physiological responses of this species to environmental extremes under field conditions. This study aimed to establish the efficacy of surgically implanted thermal radio transmitters and data loggers to measure the body temperature of free-ranging koalas across a range of environmental conditions and ambient temperatures. Five free-ranging koalas in southeast Queensland were implanted with thermal transmitters and data loggers waxed together as a single package. Body temperatures were recorded for variable periods ranging from 3 to 12 months. Diurnal rhythms in body temperature were detected irrespective of season. The long-term diurnal body temperature peak for all koalas occurred between 16:00 and 17:00 h and body temperature was 36.7–36.9 °C, the long-term nadir occurred between 07:00 and 08:00 h and body temperature was 35.4–35.7 °C. Koala body temperatures as low as 34.2 °C and as high as 39.0 °C were recorded. Thermolability became apparent when ambient temperatures were outside the deduced thermal neutral zone for koalas (14.5–24.5 °C): heat was accumulated during the day and dissipated during the cool of the night. While this study is the first to report on body temperature of free-ranging koalas in their normal behavioural context, further investigations are necessary to determine the physiological boundaries of the thermal niche for this species, in order to better equip models that will more accurately predict the impacts of climate change on koalas.

OBJECTIVE:Compare the use of four techniques to measure body temperature in koalas: intraperitoneal (thermal data logger and temperature sensitive radio transmitter), rectal (certified thermometer), tympanic (infrared thermometer), and hind foot (infrared camera). METHODS:The body temperature data collected concurrently from the intraperitoneal loggers were used as the benchmark in the analyses. RESULTS:The rectal, foot and tympanic methods consistently recorded lower body temperature when compared with the benchmark. There was a strong positive relationship (R2  = 0.79) between logger and rectal measurements, but no significant relationship between logger and foot or logger and tympanic measurements. CONCLUSION:Rectal measurements can be used to record internal body temperature, with the caveat that such measurements will generally register a temperature approximately 0.25°C lower than the actual intraperitoneal temperature.

BACKGROUND:Under predicted climate change scenarios, koala distribution in Australia is expected to be adversely affected. Recent studies have attempted to identify suitable habitat, based on models of bioclimatic regions, but to more accurately reflect the thermal tolerance and behavioural adaptations of the various regional populations, the koala's response to periods of heat stress will need to be investigated at the individual animal level.OBJECTIVE:To explore the safety and suitability of temperature-sensitive intra-abdominal implants for monitoring core body temperature in the koala.METHODS:A temperature-sensitive radio transmitter and thermal iButton data-logger, waxed together as a package, were surgically implanted into the abdominal cavity of four captive koalas. In one animal the implant was tethered and in the other three, it was left free-floating.RESULTS:After 3 months, the implants were removed and all four koalas recovered without complications. The tethering of the package in the one koala resulted in minor inflammation and adhesion, so this practice was subsequently abandoned. The free-floating deployments were complication-free and revealed a diurnal body temperature rhythm, with daily ranges of 0.4-2.8°C. The minimum recorded body temperature was 34.2°C and the maximum was 37.7°C. The difference in the readings obtained from the transmitters and iButtons never exceeded 0.3°C.CONCLUSIONS:The suitability of the surgical approach was confirmed, from both the animal welfare and data collection points of view.

BACKGROUND:Stress can play a role in disease incidence in all species via immunosuppression and has been implicated as a contributing factor in significant infectious diseases of koalas. Faecal cortisol measurement may represent a non-invasive methodology for quantifying stress in koalas.METHODS:We used an ACTH (adrenocorticotropic hormone) stimulation test (10 IU) to induce sustained secretion of cortisol, which was measured in serum samples from four koalas and subsequently it was attempted to locate a corresponding elevation in either cortisol or corticosterone measurements within the faeces.RESULTS:Although ACTH administration resulted in an elevation of serum cortisol for at least 4 h post injection, it was not possible to identify a corresponding peak in corticosterone or cortisol concentrations in extracts from the faeces, consistent with the known gut transit time of the koala.CONCLUSION:Faecal cortisol and corticosterone metabolites may not be reliable indices of acute changes in cortisol secretion in the koala and studies that attempt to use faecal cortisol as an index of stress will need to be interpreted with caution.

Australian Veterinary JournalVolume 69, Issue 9 p. 229-231 Total body water and the estimation of fat in the koala (Phascolarctos cinereus) WAH ELLIS, WAH ELLIS Koala Study Program, Department of Zoology, The University of Queensland, Queensland 4072Search for more papers by this authorFN CARRICK, FN CARRICK Koala Study Program, Department of Zoology, The University of Queensland, Queensland 4072Search for more papers by this author WAH ELLIS, WAH ELLIS Koala Study Program, Department of Zoology, The University of Queensland, Queensland 4072Search for more papers by this authorFN CARRICK, FN CARRICK Koala Study Program, Department of Zoology, The University of Queensland, Queensland 4072Search for more papers by this author First published: September 1992 https://doi.org/10.1111/j.1751-0813.1992.tb09933.xCitations: 11AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume69, Issue9September 1992Pages 229-231 RelatedInformation