page_title: Xerocole
section_title: Morphology
hierarchical_section_title: Xerocole / Thermal regulation / Morphology
caption_attribution_description: Cunningham's Skink (Egernia cunninghami) is a large skink species native to southeastern Australia
context_page_description: A xerocole, commonly referred to as a desert animal, is an animal adapted to live in the desert. The main challenges they must overcome are lack of water and excessive heat. To conserve water, they both avoid evaporation and concentrate excretions. Some are so adept at conserving water or obtaining it from food that they do not need to drink at all. To escape the desert heat, xerocoles tend to be either nocturnal or crepuscular, most active at dawn and dusk.
context_section_description: Xerocoles such as the hare have large ears that help them keep cool: when the ears stand up, blood flow increases to the numerous vessels there and heat is dissipated. However, at 48 °C (118 °F), the cape hare near Abu Dhabi, UAE sits in the shade and drapes its ears over itself, as erecting them in such weather would absorb more heat.
  Desert animals have less fat than their non-desert counterparts, as fat would act as insulation, so retaining heat. What fat they do have is localized, such as in the camel's hump or the bison's neck. In terms of fur, however, desert animals have thick insulating coats that impede the conduction of heat towards the body. The coats are not uniformly distributed, but rather leave sparsely covered patches called "thermal windows" at the axilla, groin, scrotum, and mammary glands. Heat can be dissipated from thermal windows via convection and conduction.
  Similarly, desert birds have less feathers on the underwing and flank – heat stress induces some birds to raise their wings, increasing the surface area of exposed skin. Birds adjust their feathers to create or dissipate an insulating layer, as typified by the ostrich. At high temperatures, the ostrich elevates its long dorsal feathers to create a barrier against solar radiation while allowing air to move across the skin's surface. In the cool nights, the feathers lower and interlock, trapping an insulating layer above the skin.
caption: Ectotherms, such as this Cunningham's spiny-tailed skink, often bask in the sun to regulate body temperature.
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