| Abstrakt: |
Ground squirrels, Xerus inauris,showed adaptations in behaviour, physiology and morphology to a dry and hot environment. Extreme air temperatures (Ta) were avoided by taking refuge in burrows and by shade-seeking. Direct solar irradiation was minimized by body positioning and tail erection behaviour when Taexceeded 27·5–29°C. Serum osmolality (n=17), serum urea (n=29) and serum aldosterone (n=12) concentrations were 314 ± 8·21 mosm/kg, 11·3 ± 2·06 mmol/l and 1395 ± 203·19 pmol/l, respectively. Concentrated urine and very dry faeces, with a low sodium and high potassium concentration, were produced. Rectal temperatures were positively correlated (r= 0·857; r= 0·528) with fluctuating Ta. No sweat glands and very simple sebaceous glands are observed in the skin, which is heavily pigmented with a well-developed epidermis and prominent keratin layer. |
