Responses to temperature in the dipper, Cinclus mexicanus

1. 1. Dippers have an excellent insulation as indicated by their low thermal conductance (0.33 cal/g per hr per °C) and lower critical temperature (11.5°C). This is attributed to the thickness of their extensive undercoat of down. 2. 2. The standard metabolic rate of 1.65 ml O 2/g per hr was lower t...

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Bibliographic Details
Published inComparative biochemistry and physiology Vol. 34; no. 4; pp. 859 - 869
Main Author Murrish, David E.
Format Journal Article
LanguageEnglish
Published Elsevier B.V 01.01.1970
Subjects
thermal conductance
heart-rate
breathing rate
Birds
metabolism
dippers
temperature regulation
Cinclus mexicanus
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Summary:1. 1. Dippers have an excellent insulation as indicated by their low thermal conductance (0.33 cal/g per hr per °C) and lower critical temperature (11.5°C). This is attributed to the thickness of their extensive undercoat of down. 2. 2. The standard metabolic rate of 1.65 ml O 2/g per hr was lower than predicted for passerines of the same size. 3. 3. Heart-rate, breathing rate and evaporative water loss increased rapidly when air temperature exceeded 34°C, the upper critical temperature. The percentage of metabolic heat dissipated b evaporation (evaporative efficiency) never approached 100 and the body temperature of dippers rose to lethal levels at air temperatures above 36°C. 4. 4. The uninsulated legs and feet appear necessary as avenues of heat loss at air temperatures above 36°C.
ISSN:0010-406X
DOI:10.1016/0010-406X(70)91009-1