Desert Animals: Physiological Problems of Heat and Water

Synthesises a programme of field and laboratory measurement on desert mammals, birds and reptiles, quantifying water gained and lost by every route and heat gained and lost by every route.

Studied in

Mammalia, Aves, Reptilia

Sample size

synthesis of the author’s field and laboratory programme

Desert animals survive by budgeting rather than by endurance. Most avoid the heat behaviourally, and the physiological mechanisms — concentrated urine, dry faeces, nasal water recovery, tolerance of a rising body temperature — are means of reducing loss rather than of increasing supply.

• A monograph from 1964; specific values have been refined, though the framework and most of the measurements have held.
• Concentrated on a modest number of intensively studied species.

• Desert survival

  Desert animals are not enduring the desert. They are keeping accounts — cutting losses on every route at once, and mostly arranging not to be out in the conditions at all.

• Desert survival

  A camel’s hump is fat, not water. Its real water-saving trick is to let its own body temperature swing by about six degrees through the day rather than sweating to hold it steady.

• Kangaroo rat

  A kangaroo rat can live its whole life without drinking, on water released by metabolising dry seed. It manages it by losing almost none — including by cooling its own exhaled breath to condense the water back out.