Journal of Comparative Physiology B

, Volume 164, Issue 6, pp 464-472

First online:

Thermoregulation in a large bird, the emu (Dromaius novaehollandiae)

  • S. K. MaloneyAffiliated withSchool of Biological Science, University of New South Wales
  • , T. J. DawsonAffiliated withSchool of Biological Science, University of New South Wales

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The emu is a large, flightless bird native to Australia. Its habitats range from the high snow country to the arid interior of the continent. Our experiments show that the emu maintains a constant body temperature within the ambient temperature range-5 to 45°C. The males regulate their body temperature about 0.5°C lower than the females. With falling ambient temperature the emu regulates its body temperature initially by reducing conductance and then by increasing heat production. At-5°C the cost of maintaining thermal balance is 2.6 times basal metabolic rate. By sitting down and reducing heat loss from the legs the cost of homeothermy at-5°C is reduced to 1.5 times basal metabolic rate. At high ambient temperatures the emu utilises cutaneous evaporative water loss in addition to panting. At 45°C evaporation is equal to 160% of heat production. Panting accounts for 70% of total evaporation at 45°C. The cost of utilising cutaneous evaporation for the other 30% appears to be an increase in dry conductance.

Key words

Cutaneous evaporation Panting Ratite Thermoregulation Emu,Dromaius novaehollandiae