Can birds do it too? Evidence for convergence in evaporative water loss regulation for birds and mammals

Birds have many physiological characteristics that are convergent with mammals. In the light of recent evidence that mammals can maintain a constant insensible evaporative water loss (EWL) over a range of perturbing environmental conditions, we hypothesized that birds might also regulate insensible...

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Main Authors: Eto, E., Withers, Philip, Cooper, Christine
Format: Journal Article
Published: The Royal Society Publishing 2017
Online Access:http://hdl.handle.net/20.500.11937/59419
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author Eto, E.
Withers, Philip
Cooper, Christine
author_facet Eto, E.
Withers, Philip
Cooper, Christine
author_sort Eto, E.
building Curtin Institutional Repository
collection Online Access
description Birds have many physiological characteristics that are convergent with mammals. In the light of recent evidence that mammals can maintain a constant insensible evaporative water loss (EWL) over a range of perturbing environmental conditions, we hypothesized that birds might also regulate insensible EWL, reflecting this convergence. We found that budgerigars (Melopsittacus undulatus) maintain EWL constant over a range of relative humidities at three ambient temperatures. EWL, expressed as a function of water vapour pressure deficit, differed from a physical model where the water vapour pressure deficit between the animal and the ambient air is the driver of evaporation, indicating physiological control of EWL. Regulating EWL avoids thermoregulatory impacts of varied evaporative heat loss; changes in relative humidity had no effect on body temperature, metabolic rate or thermal conductance. Our findings that a small bird can regulate EWL are evidence that this is a common feature of convergently endothermic birds and mammals, and may therefore be a fundamental characteristic of endothermy.
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institution Curtin University Malaysia
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spelling curtin-20.500.11937-594192018-11-30T06:20:36Z Can birds do it too? Evidence for convergence in evaporative water loss regulation for birds and mammals Eto, E. Withers, Philip Cooper, Christine Birds have many physiological characteristics that are convergent with mammals. In the light of recent evidence that mammals can maintain a constant insensible evaporative water loss (EWL) over a range of perturbing environmental conditions, we hypothesized that birds might also regulate insensible EWL, reflecting this convergence. We found that budgerigars (Melopsittacus undulatus) maintain EWL constant over a range of relative humidities at three ambient temperatures. EWL, expressed as a function of water vapour pressure deficit, differed from a physical model where the water vapour pressure deficit between the animal and the ambient air is the driver of evaporation, indicating physiological control of EWL. Regulating EWL avoids thermoregulatory impacts of varied evaporative heat loss; changes in relative humidity had no effect on body temperature, metabolic rate or thermal conductance. Our findings that a small bird can regulate EWL are evidence that this is a common feature of convergently endothermic birds and mammals, and may therefore be a fundamental characteristic of endothermy. 2017 Journal Article http://hdl.handle.net/20.500.11937/59419 10.1098/rspb.2017.1478 The Royal Society Publishing fulltext
spellingShingle Eto, E.
Withers, Philip
Cooper, Christine
Can birds do it too? Evidence for convergence in evaporative water loss regulation for birds and mammals
title Can birds do it too? Evidence for convergence in evaporative water loss regulation for birds and mammals
title_full Can birds do it too? Evidence for convergence in evaporative water loss regulation for birds and mammals
title_fullStr Can birds do it too? Evidence for convergence in evaporative water loss regulation for birds and mammals
title_full_unstemmed Can birds do it too? Evidence for convergence in evaporative water loss regulation for birds and mammals
title_short Can birds do it too? Evidence for convergence in evaporative water loss regulation for birds and mammals
title_sort can birds do it too? evidence for convergence in evaporative water loss regulation for birds and mammals
url http://hdl.handle.net/20.500.11937/59419