Thus 2X the water formed per g. In some respects this figure is misleading because each gm of fat has more energy so on Kcal - Kcal basis starch form more water. It does not drink because it has no access to water. It does it through many mechanisms, from behavioral to physiological. First if you have not guessed it uses metabolic water as its only water input.
Skin is waxy and impermeable to water loss.
A large loss of water due to evaporation. A animal in a terrestrial environment loses water from respiratory tissues due to the permeability of the membranes to O2 - also perm to water. In this way evaporative water loss is minimized. Although the air is always a bit more water ladened on the way out - so there is a net water loss. Absorbed water 6 Feces 2.6 Evaporation 43.9 Polar mammals .