Exploring the Role of Skin Pigmentation in the Thermal Regulation of Polar Bears and Its Implications in the Development of Biomimetic Outdoor Apparel

A popular belief for why polar bears have black skin is to increase solar heat gain from solar radiation that penetrates through a translucent fur layer made of unpigmented hollow hair. To examine the relative importance of skin color on solar heat gain, we measured thermal gradients, heat flux, and...

Full description

Saved in:
Bibliographic Details
Main Authors: Arny Leroy, David M. Anderson, Patrick Marshall, David Stark, Haskell W. Beckham
Format: Article
Language:English
Published: MDPI AG 2024-11-01
Series:Textiles
Subjects:
Online Access:https://www.mdpi.com/2673-7248/4/4/29
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1846102586450509824
author Arny Leroy
David M. Anderson
Patrick Marshall
David Stark
Haskell W. Beckham
author_facet Arny Leroy
David M. Anderson
Patrick Marshall
David Stark
Haskell W. Beckham
author_sort Arny Leroy
collection DOAJ
description A popular belief for why polar bears have black skin is to increase solar heat gain from solar radiation that penetrates through a translucent fur layer made of unpigmented hollow hair. To examine the relative importance of skin color on solar heat gain, we measured thermal gradients, heat flux, and solar transmittance through a polar bear pelt under solar irradiation while thermally anchored to a temperature-controlled plate set to 33 °C. We found that for 60–70% of the dorsal region of the pelt where the fur layer is thickest, solar energy cannot reach the skin through the fur (solar transmittance ≤ 3.5 ± 0.2%) and therefore skin color does not meaningfully contribute to solar heat gain. In contrast, skin pigmentation was important in the remaining areas of the pelt that were covered with thinner fur. This information was used to select commercially available materials according to their solar optical properties to build biomimetic outdoor apparel with enhanced solar heat gain by a factor of 3 compared to standard outerwear constructions.
format Article
id doaj-art-a5bf30e92d3e45a28e331b4286744b79
institution Kabale University
issn 2673-7248
language English
publishDate 2024-11-01
publisher MDPI AG
record_format Article
series Textiles
spelling doaj-art-a5bf30e92d3e45a28e331b4286744b792024-12-27T14:56:15ZengMDPI AGTextiles2673-72482024-11-014450752010.3390/textiles4040029Exploring the Role of Skin Pigmentation in the Thermal Regulation of Polar Bears and Its Implications in the Development of Biomimetic Outdoor ApparelArny Leroy0David M. Anderson1Patrick Marshall2David Stark3Haskell W. Beckham4Exponent, Inc., Atlanta, GA 30326, USAExponent, Inc., Atlanta, GA 30326, USAColumbia Sportswear Company, Portland, OR 97229, USAColumbia Sportswear Company, Portland, OR 97229, USAColumbia Sportswear Company, Portland, OR 97229, USAA popular belief for why polar bears have black skin is to increase solar heat gain from solar radiation that penetrates through a translucent fur layer made of unpigmented hollow hair. To examine the relative importance of skin color on solar heat gain, we measured thermal gradients, heat flux, and solar transmittance through a polar bear pelt under solar irradiation while thermally anchored to a temperature-controlled plate set to 33 °C. We found that for 60–70% of the dorsal region of the pelt where the fur layer is thickest, solar energy cannot reach the skin through the fur (solar transmittance ≤ 3.5 ± 0.2%) and therefore skin color does not meaningfully contribute to solar heat gain. In contrast, skin pigmentation was important in the remaining areas of the pelt that were covered with thinner fur. This information was used to select commercially available materials according to their solar optical properties to build biomimetic outdoor apparel with enhanced solar heat gain by a factor of 3 compared to standard outerwear constructions.https://www.mdpi.com/2673-7248/4/4/29polar bearinsulationsolar absorptancefuroutdoor apparelsolar heat gain
spellingShingle Arny Leroy
David M. Anderson
Patrick Marshall
David Stark
Haskell W. Beckham
Exploring the Role of Skin Pigmentation in the Thermal Regulation of Polar Bears and Its Implications in the Development of Biomimetic Outdoor Apparel
Textiles
polar bear
insulation
solar absorptance
fur
outdoor apparel
solar heat gain
title Exploring the Role of Skin Pigmentation in the Thermal Regulation of Polar Bears and Its Implications in the Development of Biomimetic Outdoor Apparel
title_full Exploring the Role of Skin Pigmentation in the Thermal Regulation of Polar Bears and Its Implications in the Development of Biomimetic Outdoor Apparel
title_fullStr Exploring the Role of Skin Pigmentation in the Thermal Regulation of Polar Bears and Its Implications in the Development of Biomimetic Outdoor Apparel
title_full_unstemmed Exploring the Role of Skin Pigmentation in the Thermal Regulation of Polar Bears and Its Implications in the Development of Biomimetic Outdoor Apparel
title_short Exploring the Role of Skin Pigmentation in the Thermal Regulation of Polar Bears and Its Implications in the Development of Biomimetic Outdoor Apparel
title_sort exploring the role of skin pigmentation in the thermal regulation of polar bears and its implications in the development of biomimetic outdoor apparel
topic polar bear
insulation
solar absorptance
fur
outdoor apparel
solar heat gain
url https://www.mdpi.com/2673-7248/4/4/29
work_keys_str_mv AT arnyleroy exploringtheroleofskinpigmentationinthethermalregulationofpolarbearsanditsimplicationsinthedevelopmentofbiomimeticoutdoorapparel
AT davidmanderson exploringtheroleofskinpigmentationinthethermalregulationofpolarbearsanditsimplicationsinthedevelopmentofbiomimeticoutdoorapparel
AT patrickmarshall exploringtheroleofskinpigmentationinthethermalregulationofpolarbearsanditsimplicationsinthedevelopmentofbiomimeticoutdoorapparel
AT davidstark exploringtheroleofskinpigmentationinthethermalregulationofpolarbearsanditsimplicationsinthedevelopmentofbiomimeticoutdoorapparel
AT haskellwbeckham exploringtheroleofskinpigmentationinthethermalregulationofpolarbearsanditsimplicationsinthedevelopmentofbiomimeticoutdoorapparel