Heat tolerance of monotremes

Augee, M. L.

doi:10.1016/0306-4565(76)90011-5

Cited by 22 publications

(29 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Martin (1903) measured the short-beaked echidna over a range of T a , and also concluded that they are poor thermoregulators, with a low T b that fluctuates by up to 10°C from T a of 5-35°C, with higher T a resulting in death. Robinson (1954), McMurchie and Raison (1975) and Augee (1976) also subsequently concluded that short-beaked echidnas are poor homeotherms, unable to maintain a constant T b over fluctuating T a . However, Schmidt-Nielsen et al (1966) concluded that echidnas are generally very effective thermoregulators, especially at low ambient temperatures, as did McNab (1984); echidnas maintained T b within the usual range (30-31°C) even at T a as low as 0°C, although T b increased by several degrees when exposed to high T a (30°C or above).…”

Section: Introductionmentioning

confidence: 98%

“…They apparently lack sweat glands (Martin 1903;Schmidt-Nielsen et al 1966;Augee 1976), andMartin (1903) concluded they lack vasomotor adjustments (e.g. vasoconstriction, vasodilation).…”

Section: Introductionmentioning

confidence: 99%

“…vasoconstriction, vasodilation). Augee (1976) suggested that (anaesthetised) echidnas increase ventilation but do not pant in the heat. In contrast, both long-beaked echidnas and platypus sweat to increase their evaporative heat loss (EHL; Augee 1976;Dawson et al 1978), suggesting that if short-beaked echidnas lack sweat glands then this is a derived characteristic.…”

Section: Introductionmentioning

confidence: 99%

“…Augee (1976) suggested that (anaesthetised) echidnas increase ventilation but do not pant in the heat. In contrast, both long-beaked echidnas and platypus sweat to increase their evaporative heat loss (EHL; Augee 1976;Dawson et al 1978), suggesting that if short-beaked echidnas lack sweat glands then this is a derived characteristic. As EHL is the only mechanism available for an animal to lose heat when environmental temperature is greater than T b , the echidna's inability to enhance EHL would indicate a very limited thermoregulatory capacity and necessitate inactivity and behavioural avoidance during periods of high T a (Martin 1903;Robinson 1954).…”

Section: Introductionmentioning

confidence: 99%

“…As EHL is the only mechanism available for an animal to lose heat when environmental temperature is greater than T b , the echidna's inability to enhance EHL would indicate a very limited thermoregulatory capacity and necessitate inactivity and behavioural avoidance during periods of high T a (Martin 1903;Robinson 1954). However, despite apparent lethal effects of moderately high T a in the laboratory (35°C; Martin 1903;Augee 1976), the T a of echidna's daytime shelters can exceed what has been reported as their lethal T a, so these echidnas must presumably have some physiological mechanism to tolerate high T a in the wild (Brice et al 2002a). …”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Reexamining Echidna Physiology: The Big Picture forTachyglossus aculeatus acanthion

Barker

Cooper

Withers

et al. 2016

Physiological and Biochemical Zoology

View full text Add to dashboard Cite

The early divergence of monotremes and therian mammals has resulted in considerable interest in the comparative physiology of the short-beaked echidna (Tachyglossus aculeatus), the most common and widespread living monotreme. However there are many and varied interpretations of its physiology, reflecting the many and varied studies, limitations and uncertainties of aspects of some previous studies, and potential differences between the various sub-species. Consequently, we thoroughly examine here the standardised physiology of the most widely-distributed sub-species of short-beaked echidna (T. aculeatus acanthion) over a wide range of ambient temperatures to definitively assess its physiology in a comparative context. We conclude that the low and variable body temperature of the short-beaked echidna is physiologically "primitive" but it also reflects adaptation to its myrmecophagous niche. Other aspects of its physiology are more typically mammalian. A low metabolic rate reflects its low body temperature, and ventilatory variables are matched to accommodate a modest gas exchange requirement. Thermal conductance is typical for a mammal of equivalent mass. In contrast to previous studies, we demonstrate that short-beaked echidnas have enhanced evaporative water loss above thermoneutrality, like other mammals, with a similar capacity for evaporative heat loss. Cooling of their nasal blood sinus with nasal mucous may contribute to this enhanced evaporative cooling. Their capacity to evaporatively cool explains how their distribution can include habitats where ambient temperature, even in shelters, exceeds their supposed critical thermal limit.3

show abstract

Section: Introductionmentioning

confidence: 98%

“…They apparently lack sweat glands (Martin 1903;Schmidt-Nielsen et al 1966;Augee 1976), andMartin (1903) concluded they lack vasomotor adjustments (e.g. vasoconstriction, vasodilation).…”

Section: Introductionmentioning

confidence: 99%