Organisms And Populations

The kangaroo rat in North American deserts is famous for meeting nearly all of its water requirement through internal oxidation of fat, which yields metabolic water when needed. It also has an extraordinary capacity to concentrate its urine, minimising the water lost during excretion. Drinking dew condensed on fur is not its primary mechanism and is not the textbook adaptation highlighted for this animal. Storing water in a specialised bladder is incorrect because the kangaroo rat does not possess such an organ; this is more associated with some amphibians. Absorbing moisture through the skin is wrong since mammalian skin is keratinised and largely impermeable, preventing significant water uptake. As described in NCERT Class 12, Chapter 13 (Organisms and Populations), desert organisms display physiological and behavioural adaptations to conserve water and tolerate heat. Comparable adaptations are seen in desert plants such as Opuntia, which lack leaves and photosynthesise through flattened stems to reduce transpirational water loss. These convergent strategies show how unrelated organisms independently solve the same problem of water scarcity. Plausibility check: since the animal reportedly never drinks free water yet maintains hydration, the only self-consistent source is biochemical, namely water generated during the catabolic oxidation of stored fat, confirming the metabolic-water explanation.