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Animal coat color and radiative heat gain: A re-evaluation

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Thermal resistance and heat gain from simulated solar radiation were measured over a range of wind velocities in black and white pigeon plumages. Plumage thermal resistance averaged 39% (feathers depressed) or 16% (feathers erected) of that of an equivalent depth of still air. Feather erection increased plumage depth four-fold and increased plumage thermal resistance about 56%. At low wind speeds, black plumages acquired much greater radiative heat loads than did white plumages. However, associated with the greater penetration of radiation into light than dark plumages, the radiative heating of white plumages is affected less by convective cooling than is that of black plumages. Thus, the heat loads of black and white plumages converge as wind speed is increased. This effect is most prominent in erected plumages, where at wind speeds greater than 3 ms−1 black plumages acquire lower radiative heat loads than do white plumages. These results suggest that animals with dark-colored coats may acquire lower heat loads under ecologically realistic conditions than those forms with light-colored coats. Thus, the dark coat colors of a number of desert species and the white coat color of polar forms may be thermally advantageous.

These results are used to test a new general model that accounts for effects of radiation penetration into a fur or feather coat upon an animal's heat budget. Even using simplifying assumptions, this model's predictions closely match measured values for plumages with feathers depressed (the typical state). Predictions using simplifying assumptions are less accurate for erected plumages. However, the model closely predicts empirical data for erected white plumages if one assumption is obviated by additional measurements. Data are not sufficient to judge whether this is also the case for erected black plumages.

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A :

body surface area (m2)

a L :

long-wave absorptivity of coat

a s :

short-wave absorptivity of coat

d :

characteristic dimension (m)

E :

evaporative water loss (kg m−2 s−1)

h :

coat thermal conductance (W m−2 °C−1)

k :

convection constant (s1/2 m−1)

l :

coat thickness (m)

L i :

long-wave irradiance at coat surface (W m−2)

M :

metabolic heat production (W m−2)

m :

body mass (kg)


plumage mass (kg)

p :

probability per unit coat depth that a penetrating ray will strike a coat element (m−1)

q(Z) :

radiation absorbed at level z (W m−2)

R abs :

radiation absorbed by animal (W m−2)

r e :

external resistance to convective and radiative heat transfer (s m−1)

r Ha :

boundary layer resistance to convective heat transfer (s m−1)

r Hb :

whole-body thermal resistance (s m−1)

r Hc :

coat (plumage) thermal resistance (s m−1)

r Ht :

tissue thermal resistance (s m−1)

r s :

apparent resistance to radiative heat transfer (s m−1)


thermal resistance from level z to coat surface (s m−1)

S i :

short-wave irradiance at coat surface (W m−2)

S :

radiant flux going toward skin surface (W m−2)

S + :

radiant flux going away from skin surface (W m−2)

T a :

air temperature (°C)

T b :

core body temperature (°C)

T e :

equivalent black-body temperature (°C)

T′ e :

air temperature plus temperature increment due to longwave radiation (°C)

u :

wind velocity (m s−1)

V :

heat load on animal from short-wave radiation (W m−2)


depth within coat (m)


short-wave absorptivity of individual hairs or feather elements






latent heat of vaporization of water (J kg−1)


short-wave reflectivity of individual hairs or feather elements


short-wave reflectivity of coat


short-wave reflectivity of skin

ρc p :

volumetric specific heat of air (J m−3 °C−1)


Stefan-Boltzmann constant (W m−2 °K−4)


short-wave transmissivity of individual hairs or feather elements


short-wave transmissivity of coat


  • Bakken, G.S., Gates, D.M.: Heat transfer analysis of animals: some implications for field ecology, physiology, and evolution. In: Perspectives in biophysical ecology (eds. D.M. Gates, R.B. Schmerl), pp. 255–290. Berlin-Heidelberg-New York: Springer 1975

    Google Scholar 

  • Buxton, P.A.: Animal life in deserts. London: Edward Arnold and Co. 1923

    Google Scholar 

  • Calder, W.A., King, J.R.: Thermal and caloric relations of birds. In: Avian biology, Vol. 4 (eds. D.S. Farner, J.R. King), pp. 259–413. New York: Academic Press 1974

    Google Scholar 

  • Campbell, G.S.: An introduction to environmental biophysics. Berlin-Heidelberg-New York: Springer 1977

    Google Scholar 

  • Cena, K.: Absorption of solar radiation by cattle and horses with various coat colors. Acta Agr. Silv.6, 93–138 (1966)

    Google Scholar 

  • Cena, K., Monteith, J.L.: Transfer processes in animal coats. I. Radiative transfer. Proc. roy. Soc. Lond. B188, 377–394 (1975a)

    Google Scholar 

  • Cena, K., Monteith, J.L.: Transfer processes in animal coats. II. Conduction and convection. Proc. roy. Soc. Lond. B188, 395–411 (1975b)

    Google Scholar 

  • Cowles, R.B.: Black pigmentation: Adaptation for concealment or heat conservation? Science158, 1340–1341 (1967)

    Google Scholar 

  • Dawson, T.J., Brown, G.D.: A comparison of the insulative and reflective properties of the fur of desert kangaroos. Comp. Biochem. Physiol.37, 23–38 (1970)

    Google Scholar 

  • Fuchs, M., Hadas, A.: Analysis of the performance of an improved soil heat flux transducer. Soil Sci. Soc. Am. Proc.37, 173–175 (1973)

    Google Scholar 

  • Grant, G.S., Hogg, N.: Behavior of late-nesting Black Skimmers at Salton Sea California. Western Birds7, 73–80 (1976)

    Google Scholar 

  • Grum, F.: Artificial light sources for simulating natural daylight and skylight. Appl. Opt.7, 183–187 (1968)

    Google Scholar 

  • Hamilton, W.J., III: Life's color code New York: McGraw-Hill 1973

    Google Scholar 

  • Hamilton, W.J., III, Heppner, F.: Radiant solar energy and the function of black homeotherm pigmentation: an hypothesis. Science155, 196–197 (1967)

    Google Scholar 

  • Hillman, P.E.: simulation and modeling of transient thermal responses of the western fence lizard,Sceloporus occidentalis Ph. D. Dissertation, Washington State University (1974)

  • Howell, T.R., Araya, B., Millie, W.R.: Breeding biology of the Gray Gull,Larus modestus. Univ. Calif. Publ. Zool.104, 1–57 (1974)

    Google Scholar 

  • Howell, T.R., Bartholomew, G.A.: Temperature regulation in the Sooty TernSterna fuscata. Ibis104, 98–105 (1962)

    Google Scholar 

  • Hutchinson, J.C.D., Brown, G.B.: Penetrance of cattle coats by radiation. J. appl. Physiol.26, 454–464 (1969)

    Google Scholar 

  • Idso, S.B.: A simple technique for the calibration of long-wave radiation probes. Agr. Meterol.8, 235–243 (1971)

    Google Scholar 

  • Kovarik, M.: Flow of heat in an irradiated protective cover. Nature201, 1085–1087 (1964)

    Google Scholar 

  • Lustick, S.: Bird energetics: effects of artificial radiation. Science163, 387–390 (1969)

    Google Scholar 

  • Maclean, G.L.: The breeding biology and behavior of the Doublebanded CourserRhinoptilus africanus (Temminck). Ibis109, 556–569 (1967)

    Google Scholar 

  • Meinertzhagen, R.: Birds of Arabia. Edinburg: Oliver and Boyd 1954

    Google Scholar 

  • Monteith, J.L.: Principles of environmental physics. New York: American Elsevier Publ. Co. 1973

    Google Scholar 

  • Naik, R.M., George, P.V., Dixit, D.B.: some observations on the behavior of the incubating Red-wattled Lapwing,Vanellus indicus (Bodd.). J. Bombay Nat. Soc.58, 223–230 (1961)

    Google Scholar 

  • Pennycuick, C.J.: Power requirements for horizontal flight in the pigeon,Columba livia. J. exp. biol.49, 527–555 (1968)

    Google Scholar 

  • Pennycuick, C.J.: The mechanics of bird migration. Ibis111, 525–556 (1969)

    Google Scholar 

  • Robinson, D.E., Campbell, G.S., King, J.R.: An evaluation of heat exchange in small birds. J. comp. Physiol.105, 153–166 (1976)

    Google Scholar 

  • Tanner, C.B.: Basic instrumentation and measurements for plant environment and micrometerology. Univ. Wisconsin, Dept. Soils Sci. Bull.6, S 1–15 (1963)

    Google Scholar 

  • Walsberg, G.E.: Ecology and energetics of contrasting social systems inPhainopepla nitens (Aves: Ptilogonatidae) Univ. Calif. Publ. Zool.108, 1–63 (1977)

    Google Scholar 

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Walsberg, G.E., Campbell, G.S. & King, J.R. Animal coat color and radiative heat gain: A re-evaluation. J Comp Physiol B 126, 211–222 (1978).

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