Skip to main content Accessibility help

Relationships between integumental characteristics and thermoregulation in South American camelids

  • M. Gerken (a1)


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 vicuña (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.


Corresponding author



Hide All
Allain, D, Renieri, C 2010. Genetics of fibre production and fleece characteristics in small ruminants, Angora rabbit and South American camelids. Animal 4, 14721481.
Allen, TE, Bligh, J 1969. A comparative study of the temporal pattern of cutaneous water vapor loss from some domesticated mammals with epitrichial sweat glands. Comparative Biochemistry and Physiology 31, 347363.
Antonini, M 2010. Hair follicle characteristics and fibre production in South American Camelids. Animal 4, 14601471.
Atlee, BA, Stannard, AA, Fowler, ME, Willemse, T, Ihrke, PJ, Olivry, T 1997. The histology of normal llama skin. Veterinary Dermatology 8, 165176.
Bligh, J 1998. Mammalian homeothermy: an integrative thesis. Journal of Thermal Biology 23, 143258.
Bligh, J, Baumann, I, Sumar, J, Pocco, F 1975. Studies of body temperature patterns in South American Camelidae. Comparative Biochemistry and Physiology A 50, 701708.
Bonacic, C, Feber, RE, Macdonald, DW 2006. Capture of the vicuña (Vicugna vicugna) for sustainable use: animal welfare implications. Biological Conservation 129, 543550.
Bulgarella, M, de Lamo, D 2005. Thermal conductance of guanaco (Lama guanicoe) pelage. Journal of Thermal Biology 30, 569573.
Dawes, K 1973. Objective Measurement of Wool. New South Wales University Press, Sydney, Australia.
de Lamo, DA 1990. Temperature regulation and energetics of the guanaco (Lama guanicoe). PhD, University of Illinois, Urbana-Champaign. 184pp.
de Lamo, DA, Sanborn, AF, Carrasco, CD, Scott, DJ 1998. Daily activity and behavioral thermoregulation of the guanco (Lama guanicoe) in winter. Canadian Journal of Zoology 76, 13881393.
de Lamo, DA, Lacolla, D, Heath, JE 2001. Sweating in the guanaco (Lama guanicoe). Journal of Thermal Biology 26, 7783.
Duga, L 1986. Características más importantes de las fibras provenientes de camélidos sudamericanos (llamas, alpacas y sus cruzas y guanacos). Proceedings of the LANAS, Seminario Cientifico Regional, 1985, Montevideo, Uruguay, Editorial Hemisfero Sur, pp. 215–217.
Eckhart, L, Valle, LD, Jaeger, K, Ballaun, C, Szabo, S, Nardi, A, Buchberger, M, Hermann, M, Alibardi, L, Tschachler, E 2008. Identification of reptilian genes encoding hair keratin-like proteins suggests a new scenario for the evolutionary origin of hair. Proceedings of the National Academy of Sciences of the United States of America 105, 1841918423.
Eltringham, SK, Jordan, W 1981. The vicuña of the Pampa Galeras National Reserve. The conservation issue. In Problems in management of locally abundant wild animals (ed. PA Jewell and S Holt), pp. 277289. Academic Press, New York, USA.
Flores Ochoa, J 1994. Man’s relationship with the camelids. In Gold of the Andes: the llama, alpacas, vicuñas and guanacos of South America (ed. J Martinez), pp. 36286. FO Patthey and sons, Barcelona, Spain.
Fowler, ME 1994. Hyperthermia in llamas and alpacas. The veterinary clinics of North America. Food Animal Practice 10, 309317.
Fowler, ME 1998. Medicine and Surgery of South American Camelids, 2nd edition. Iowa State University Press, Ames, IA, USA.
Galbraith, H 2010a. Fundamental hair follicle biology and fine fibre production in animals. Animal 4, 14901509.
Galbraith, H 2010b. In vitro methodology, hormonal and nutritional effects and fibre production in isolated ovine and caprine anagen hair follicles. Animal 4, 14821489.
Gatenby, RM, Monteith, JL, and Clark, JA 1983. Temperature and humidity gradients in a sheep’s fleece. II. The energetic significance of transients. Agricultural Meteorology 29, 83101.
Gerken, M 1996. Application of infrared thermography to evaluate the influence of the fibre on body surface temperature in llamas. In Proceedings of the 2nd European Symposium on South American Camelids (ed. M Gerken and C Renieri), 30 August to 2 September 1995, Camerino, pp. 255261. Università degli studi di Camerino, Camerino, Italy.
Gerken, M, Snell, H 1998. Tierschutzfragen bei der Haltung von Neuweltkameliden in Europa. Proceedings of the Tagung Tierschutz und Nutztierhaltung, 5 to 7 March 1998, Nürtingen, Germany, DVG, pp. 205–211.
Gerken, M, Bramsmann, S, Dörl, J 2003. Evaluation of thermoregulation in llamas (Lama glama). Proceedings of the 3 Congreso Mundial sobre Camelidos, 15 to 18 October 2003, Potosí, Bolivia, vol. 1, pp. 135–140.
Gerken, M, Afnan, R, Dörl, J 2006. Adaptive behaviour in chickens in relation to thermoregulation. Archiv für Geflügelkunde 70, 199207.
Grigg, GC, Beard, LA, Augee, ML 2004. The evolution of endothermy and its diversity in mammals and birds. Physiological and Biochemical Zoology 77, 982997.
Hansen, PJ 1990. Effects of coat colour on physiological responses to solar radiation in Holsteins. Veterinary Records 127, 333334.
Harris, GD, Huppi, HD, Gessaman, JA 1985. The thermal conductance of winter and summer pelage of Lepus californicus. Journal of Thermal Biology 10, 7981.
Heath, AM, Navarre, CB, Simpkins, A, Purohit, RC, Pugh, DG 2001. A comparison of surface and rectal temperatures between sheared and non-sheared alpacas (Lama pacos). Small Ruminant Research 39, 1923.
Jessen, C 2001. Temperature regulation in humans and other mammals. Springer-Verlag, Berlin, Heidelberg, New York.
Laker, J 2006. Wildlife or livestock? Divergent paths for the vicuña as priorities change in the pursuit of sustainable development. In South American camelids research (ed. M Gerken and C Renieri), pp. 2627. vol. 1. Wageningen Academic Publishers, Wageningen, The Netherlands.
McArthur, AJ 1991. Thermal radiation exchange, convection and the storage of latent heat in animal coats. Agricultural Forest Meteorology 53, 325336.
McCafferty, DJ 2007. The value of infrared thermography for research on mammals: previous applications and future directions. Mammal Review 37, 207223.
Meng, J, Wyss, AR 1997. Multituberculate and other mammal hair recovered from Palaeogene excreta. Nature 385, 712714.
Milz, C 2001. Vergleichende Untersuchungen zum Verhalten von Lamas und Schafen auf der Weide. Inaugural Dissertation, Justus Liebig University Giessen.
Moen, AN 1973. Wildlife Ecology. WH Freeman Co, San Francisco, CA, USA.
Morrison, P 1966. Insulative flexibility in the guanaco. Journal of Mammalogy 47, 1823.
Navarre, CB, Heath, AM, Wenzel, J, Simpkins, A, Blair, E, Belknap, E, Pugh, DG 2001. A comparison of physical examination and clinicopathologic parameters between sheared and nonsheared alpacas (Lama pacos). Small Ruminant Research 39, 1117.
Patthey Salas, JF 1994. Textile Process for South American camelids. In Proceedings of the European Symposium on South American Camelids (ed. M Gerken and C Renieri), pp. 167175. Università degli studi di Camerino, Camerino, Italy.
Phan, K-H 1994. Neue Erkenntnisse über die Morphologie von Kreatinfasern mit Hilfe der Elektronenmikroskopie. Thesis RWTH Aachen University. Verlag Mainz, Wissenschaftsverlag, Aachen.
Pilters, H 1954. Untersuchungen über angeborene Verhaltensweisen bei Tylopoden, unter besonderer Berücksichtigung der neuweltlichen Formen. Zeitschrift für Tierpsychologie 11, 213303.
Rosenmann, M, Morrison, P 1963. Physiological response to heat and dehydration in the guanaco. Physiological Zoology 36, 4551.
Rotter, D 1991. Llamas can Beat the Heat. R&R Press, Dripping Springs, TX, USA.
Ruben, J 1995. The evolution of endothermy in mammals and birds: from physiology to fossils. Annual Review of Physiology 57, 6995.
Russel, AJF, Redden, H 1994. Effects of season and nutrition on fibre growth in llamas. In Proceedings European Symposium on South American Camelids (ed. M Gerken and C Renieri), pp. 179186. Università degli studi di Camerino, Camerino, Italy.
Schmidt-Nielsen, K 1997. Animal Physiology, 5th edition. Cambridge University Press, Cambridge, UK.
Schwalm, A, Erhardt, G, Gerken, M, Moors, E, Gauly, M 2008. Einfluss von Hitzebelastung auf Thermoregulation und Fruchtbarkeitsleistung bei geschorenen und ungeschorenen männlichen Lamas (Lama glama). Tierärztliche Praxis 36, 324328.
Turnpenny, JR, McArthur, AJ, Clark, JA, Wathes, CM 2000. Thermal balance of livestock 1. A parsimonious model. Agricultural and Forest Meteorology 101, 1527.
Walsberg, GE, Campbell, GS, and King, JR 1978. Animal coat color and radiative heat gain: a re-evaluation. Journal of Comparative Physiology B 126, 211222.


Relationships between integumental characteristics and thermoregulation in South American camelids

  • M. Gerken (a1)


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed