In the face of climate change, the life history traits of large terrestrial mammals will prevent them from adapting genetically at a sufficient pace to keep track with changing environments, and habitat fragmentation will preclude them from shifting their distribution range. Predicting how habitat-bound large mammals will respond to environmental change requires measurement of their sensitivity and exposure to changes in the environment, as well as the extent to which phenotypic plasticity can buffer them against the changes. Behavioural modifications, such as a shift to nocturnal foraging or selection of a cool microclimate, may buffer free-living mammals against thermal and water stress, but may carry a cost, for example by reducing foraging time or increasing predation risk. Large mammals also use physiological responses to buffer themselves against changing environments, but those buffers may be compromised by a changing physical environment. A decrease in the available food energy or water leads to a trade-off in which the precision of homeothermy is relaxed, resulting in large daily fluctuations in body temperature. Understanding how large mammals prioritise competing homeostatic systems in changing environments, and the consequences of that prioritisation for their fitness, requires long-term monitoring of identifiable individual animals in their natural habitat. Although body size predicts general ecological and energetic patterns of terrestrial mammals, high intraspecific and interspecific variability means that a species-directed approach is required to accurately model responses of large mammals to climate change.

Homeothermy

Ectotherm

Microclimate

Habitat Fragmentation

Environmental change

Adaptability

10.1186/s40665-016-0024-1

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Citations (161)

Ameliorating the adverse cardiorespiratory effects of chemical immobilization by inducing general anaesthesia in sheep and goats: implications for physiological studies of large wild mammals

Journal of Comparative Physiology B (2018)

Adian Izwan Edward P. Snelling Roger S. Seymour Leith C. R. Meyer Andrea Fuller

10.1007/s00360-018-1184-z

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Absence of selective brain cooling in unrestrained baboons exposed to heat

AJP Regulatory Integrative and Comparative Physiology (2007)

Shane K. Maloney Duncan Mitchell Graham Mitchell Andrea Fuller

To test whether baboons are capable of implementing selective brain cooling, we measured, every 5 min, the temperature in their hypothalamus, carotid arterial bloodstream, and abdominal cavity. The baboons were unrestrained and exposed to 22 degrees C for 7 days and then to a cyclic environment with 15 degrees C at night and 35 degrees C during the day for a further 7 days. During the latter 7 days some of the baboons also were exposed to radiant heat during the day. For three days, during heat exposure, water was withheld. At no time was the hypothalamus cooler than carotid arterial blood, despite brain temperatures above 40 degrees C. With little variation, the hypothalamus was consistently 0.5 degrees C warmer than arterial blood. At high body temperatures, the hypothalamus was sometimes cooler than the abdomen. Abdominal temperature was more variable than arterial blood and tended to exceed arterial blood temperature at higher body temperatures. Hypothalamic temperature cooler than a warm abdomen is not evidence for selective brain cooling. In species that can implement selective brain cooling, the brain is most likely to be cooler than carotid arterial blood when an animal is hyperthermic, during heat exposure, and also dehydrated and undisturbed by human presence. When we exposed baboons to high ambient temperatures while they were water deprived and undisturbed, they never implemented selective brain cooling. We conclude that baboons cannot implement selective brain cooling and can find no convincing evidence that any primate species can do so.

10.1152/ajpregu.00809.2006

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Rumen temperature is a reliable proxy of core body temperature in sheep (

Animal Production Science (2022)

Kristine Vesterdorf D. T. Beatty A. Barnes Shane K. Maloney

Context In ruminant animals, such as sheep, the maintenance of a stable core body temperature is achieved through the controlled process of thermoregulation. The live export of sheep from Australia can expose sheep to heat stress, especially when vessels near, or cross, the equator, that can impact on animal welfare by causing hyperthermia. Aim The use of thermologgers located in the rumen of sheep could provide a direct, real-time method to monitor the thermal status of sheep during live export without the need to handle animals during shipping. We determined the relationship between core temperature and rumen temperature during changes in various factors that impact on an animal’s heat balance. Methods Sixteen wethers were implanted with thermologgers in the rumen to measure rumen temperature and in the abdominal cavity to measure core temperature. The sheep were exposed to environmental conditions similar to those experienced by sheep on live export vessels. The environment was assessed using the wet-bulb temperature. In the first trial, eight Merinos were shorn while the remaining eight retained their fleece. In the second trial all sheep were shorn, and eight sheep were offered a chaff diet and eight a pelletised diet while the wet bulb temperature increased. The rumen and core temperatures were compared. Key results We show that when core temperature increased during exposure to heat load, so did rumen temperature and, despite relatively large changes in overall body temperature, the difference between these temperatures remained stable. The daily average relationship between rumen and core temperatures was 0.5 ± 0.1°C and that difference was not affected by water ingestion, length of fleece, diet composition, or exposure to hot and humid conditions similar to those reported on live export vessels. Conclusion and implications By subtraction of 0.5°C from the measured rumen temperature in live export sheep, the use of rumen thermologgers would provide a reliable measure of core temperature and hence an indication of the thermal status of the sheep throughout the export journey.

10.1071/an21490

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Citations (4)

Richard Casey and Mahatma Gandhi

Monthly, The (2009)

Shane K. Maloney Chris Grosz

The meeting between Mahatma Gandhi and Richard Casey, the governor of Bengal, in Calcutta in 1945 is discussed. Their friendly interactions to discuss the issue of Indian independence and the division of India are described.

BENGAL

Independence

Governor

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Billy Hughes and Woodrow Wilson

Monthly, The (2007)

Shane K. Maloney Chris Grosz

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