Xerocole

A xerocole (from Greek xēros /ˈzɪroʊs/ 'dry' and Latin col(ere) 'to inhabit'),[2][3][4] is a general term referring to any animal that is adapted to live in a desert.

[5] Amphibious xerocoles, such as species of the frog genus Phyllomedusa, have wax-like coatings on their skin to reduce water loss.

[9][12] The process, called respiratory heat exchange, works best when the walls of the nasal passage have a large surface area.

[5] Similarly, many rodents and marsupials lick themselves to spread saliva, though this only remains effective for a short time, and requires the fur to become very damp.

Desert mammals also have longer loops of Henle, structures whose efficiency in concentrating urine is directly proportional to their length.

[23] Seed-eating rodents maintain a low metabolic rate to reduce water lost to respiration (and to prevent their burrow from overheating).

Some xerocoles are able to obtain water from halophytic (saltwater) plants, as they can metabolize high amounts of oxalic acid and produce very concentrated urine.

[7][27] 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.

[5] In terms of fur, however, desert animals have thick insulating coats that impede the conduction of heat towards the body.

[7] The coats are not uniformly distributed, but rather leave sparsely covered patches called "thermal windows" at the axilla, groin, scrotum, and mammary glands.

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.

[5] As ectotherms are usually small and unable to store their own body heat, they quickly take on the external temperature of the environment, which necessitates controlled microenvironments.

As such, they spend their nights in burrows or crevices, where they create warm environments by quickly generating metabolic heat.

[9] Some xerocoles change their activity patterns depending on the season: nocturnal ants, for example, become diurnal during colder periods.

[10] Unlike hibernation, which leads to a state of torpor, estivation induces lethargy, and can go unnoticed in some animals if their body temperature is not measured.

[13] Xerocoles are usually light and sandy in color as a means to reflect solar radiation and reduce heat absorption.

They become darker when burrowing and lighter when basking – both the desert iguana and the zebra-tailed lizard become so pale that they appear to shine due to the amount of light they reflect.

[32] Most desert lizards also have a black peritoneal lining in their abdominal cavity to absorb UV radiation and prevent it from damaging internal organs.

[29][32] Desert animals such as the camel, addax, and kangaroo rat have large feet to prevent them from sinking in the sand.