Why cats spend so much time grooming.
A cat licks its fur not only to keep itself clean, but to smooth its fur so that it acts as a more efficient insulating layer. And cold is not the only problem. Cats can overheat in summertime. They do not have sweat glands all over their bodies like we do, so they cannot use sweating as a rapid method of cooling. Panting help, but is not enought. The solution ts to lick repeatedly at the fur and desposit on it as much saliva as possible. The evaporation of this saliva acts in the same way as the evaporation of sweat on our skin. Sunlight on their fur also produces vitamin D. They acquire this crucial additive to their diets by licking their tongues over their sun-warmed fur.