Heterothermia in pigeons and doves reduces energetic costs

Two patterns of heterothermia were demonstrated for three species of pigeon s (Columbidae): Controlled hyperthermia as a physiological strategy of the arid-adapted Australian Diamond Dove and African Namaqua Dove to minimize h eat stress when exposed to high temperatures and Torpor as an energy-saving mechanism at low environmental temperatures. This mechanism was most prono unced in the fruit-eating Cloven-feathered Dove (minimal body temperature T -b = 25 degreesC, reduction of metabolic rate by 67%). Hence, heterothermia is regarded as a means of adaptation to variable and unpredictable environ mental conditions, playing an important role in the ecological radiation of the Columbidae. (C) 2001 Elsevier Science Ltd. All rights reserved.