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

Walsberg, Glenn E.; Campbell, Gaylon S.; King, James R.

doi:10.1007/bf00688930

Cited by 173 publications

(120 citation statements)

References 18 publications

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“…First, predator-prey interactions may be at the heart of Gloger's rule if dark and pale individuals are cryptic in different habitats (Miller and Miller 1951, Burtt 1981, Zink and Remsen 1986. Second, animals may be darker in wetter habitats because melanin pigments play a role in thermoregulation, or because heavily pigmented feathers repel water better, allowing the body to dry more rapidly (Heppner 1970, Walsberg et al 1978, Burtt 1981, ClusellaTrullas et al 2008. Third, melanin pigments may protect the integument against ectoparasites (Ruiz- De-Castañeda et al 2012) and bacteria (Burtt andIchida 2004, Goldstein et al 2004) that thrive in warm and humid habitats (Guernier et al 2004).…”

Section: Introductionmentioning

confidence: 99%

Gloger's rule in North American Barn Owls

Roulin

Randin

2015

The Auk

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Section: Introductionmentioning

confidence: 99%

Gloger's rule in North American Barn Owls

Roulin

Randin

2015

The Auk

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“…the environment (Walsberg et al, 1978;de Lamo, 1990;Schmidt-Nielsen, 1997;Bligh, 1998;Jessen, 2001). The capacity for piloerection by muscles at the base of the hairs allows the variation of the supracutaneous insulation provided by still air trapped in the hair coat, thus changing the area of the hairs relative to the skin (Bligh, 1998), comparable to feathers in birds (Gerken et al, 2006).…”

Section: Human Effectsmentioning

confidence: 99%

“…A fleece contains air spaces with water vapour that is in equilibrium with the water either absorbed or adsorbed on the wool fibres (Gatenby et al, 1983), with the latent heat of vaporisation of water having an important effect on the energy budget of the animal (Walsberg et al, 1978). When the skin is covered by a heavy pelage, passive transfer of water vapour across the skin is negligible.…”

Section: Temperature Within the Fleecementioning

confidence: 99%

“…Heat dissipation from the fleece is inhibited if the fibre coat is dirty, matted, excessively long or wet (Fowler, 1994). Solar radiation may penetrate into the coat and the depth of penetration depends on the colour (Walsberg et al, 1978;Hansen, 1990;Turnpenny et al, 2000) and the density of the coat. However, the fleece does not represent a purely physical system because the microclimate next to its skin is subject to control by the animal.…”

Section: Temperature Within the Fleecementioning

confidence: 99%

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Relationships between integumental characteristics and thermoregulation in South American camelids

Gerken

2010

Animal

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Hair fibre is regarded as a unique mammalian feature with an important role for endothermy. Artificial selection for hair characteristics resulted in marked changes with regard to follicle number, type, distribution, growth and natural shedding. This review focuses on the fine fibre-producing South American camelids (SACs) and the relationship between their hair coat and thermoregulation. SACs have developed several special integumental characteristics. While the hair coat of the wild lamoids vicuñ a (Vicugna vicugna) and guanaco (Lama guanicoe) is formed by two types of hair (the coarse outer guard hairs and a finer undercoat), the domesticated llamas (Lama glama) and alpaca (Lama pacos) exhibit variably double coat and predominantly single coat, respectively. The distribution of the hair coat across the body is not homogenous. Thermal windows with shorter hair or thinner skin can be identified at the ventral abdomen, axillary space and inside of the thighs (about 20% of the skin), thus allowing to modulate heat dissipation. In contrast to sheep wool, lamoid fibres are mainly medullated. The thermal conductance of summer pelage was higher than that of the winter fleece and highest for the axillar and lower flanks. Lamoids have developed behavioural strategies to modify heat loss by adopting specific postures according to ambient conditions by closing or opening the thermal windows. Energy savings of 67% attributed to posture were calculated. SACs have shown to be able to adapt to a broad range of different climatic conditions. The specific integumental characteristics of SACs indicate that they have developed adaptation mechanisms particularly suited for cooler climates. Accordingly, hyperthermia might become a problem in hot, humid areas outside of their original habitat. Several studies showed the beneficial effect of shearing against heat stress. In particular, fertility in males exposed to heat stress may be improved by shearing. Infrared thermography reveals that in shorn animals the heat is radiated across the entire body surface and is not restricted to the thermal windows. However, shearing also changes the conditions of the protective layer, resulting in a loss of thermal conductance that may result in adverse effects when animals are kept under cold temperatures. The length of residual fibre appears to be crucial in avoiding excessive heat loss in a cold environment, as demonstrated by shearing experiments with different shearing machines. There is, therefore, potential for welfare considerations to conflict with industrial demands for fibre length or homogenous quality.

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“…Na ausência de uma capa de cobertura espessa, o calor é perdido diretamente da superfície cutânea para o ambiente, o que não ocorre em superfície coberta por uma capa, na qual a troca de calor do corpo com o ambiente é determinada pelo isolamento térmico proporcionado pela capa (Davis & Birkebak, 1974;Cena & Monteith, 1975abc;Ehrlemark & Sallvik, 1996;Berman, 2004). Cada tipo de cobertura adiciona grau de isolamento térmico diferente (Blaxter et al, 1959;Treggear, 1965;Walsberg et al, 1978).…”

Section: Introductionunclassified

Efeitos da temperatura e da movimentação do ar sobre o isolamento térmico do velo de ovinos em câmara climática

Maia

Silva

Andrade³

2009

R. Bras. Zootec.

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RESUMO -Foram utilizados dez ovinos da raça Corriedale -cinco machos e cinco fêmeas com pesos entre 52,2 e 87,6 kg -com o objetivo de avaliar o efeito da combinação da movimentação do ar (0 e 5,0 m/s) com a temperatura do ar (25, 30 e 40ºC) sobre a temperatura retal (T R , ºC), da epiderme (T E , ºC), da superfície do velo (T V , ºC) e do interior do velo (T I , ºC) e a espessura do velo (E V , cm) e suas relações com o isolamento térmico do velo. A presença de vento não teve efeito sobre as variáveis estudadas, o que sugere que fluxo de ar (<5,0 m/s) paralelo ao eixo corporal do animal tem pouco efeito sobre o isolamento térmico do velo, independentemente da temperatura do ar, que se mostrou altamente correlacionada, de forma positiva, com as temperaturas retal, do velo, do interior do velo e da epiderme. Sob temperaturas inferiores a 30ºC, a transferência de calor através do velo ocorreu via condução e convecção livre, enquanto sob altas temperaturas (>40ºC) o fluxo de calor sensível não foi significativa. Palavras-chave: vento, calor sensível, ovinos Effect of temperature and air velocity on the thermal insulation of the fleece of sheep in climatic chamberABSTRACT -Ten Corriedale sheep were evaluated, five males and five females with 52.2 to 87.6 kg of body weight, to evaluate the effect of air velocity (0 and 5 m/s) and temperature (25, 30 and 40ºC) on rectal temperature (T R , ºC), skin temperature (T E , ºC), fleece surface temperature (T V , ºC), temperature inside the fleece (T I , ºC), and fleece thickness (E V , cm) and their relationship with fleece thermal insulation. The results showed that air velocity did not affect the studied traits, suggesting that airflow <5.0 m/s parallel to the fleece had little effect on fleece thermal insulation, regardless the air temperature. Air temperature was highly correlated with T R , T E , T I and T V . Under air temperatures below 30°C, the heat transfer through the fleece was dominated by conduction and free convection, while under high temperatures (>40°C), the sensible heat flow was not significant.

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

Cited by 173 publications

References 18 publications

Gloger's rule in North American Barn Owls

Gloger's rule in North American Barn Owls

Relationships between integumental characteristics and thermoregulation in South American camelids

Efeitos da temperatura e da movimentação do ar sobre o isolamento térmico do velo de ovinos em câmara climática

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