The rat in North American deserts is capable of meeting all its water requirements through its internal fat oxidation. It is an example of
Adaptations are the attribute of the organisms (morphological, physiological, behavioural) that enables the organism to survive and reproduce in its habitat. Many adaptations have evolved over a long evolutionary time and are genetically fixed.
Even in the absence of water, Kangaroo rat in North American deserts is capable of meeting all its water requirements from its internal fat oxidation in which water is produced as a byproduct. Also it can concentrate its urine. It is a physiological adaptation.