A cat will groom more in hot weather than in cold weather. It is thought that cats domesticated themselves. They saw a good place to live among humans, and moved in. When a population of cats becomes crowded, the cats alter their behavior and become more like lions. The females share care of the kittens, nursing all the babies in the group.
Cats have few eating problems.
While there are fat cats, most cats will naturally adjust their caloric intake according to their physical needs. Dominance relationship among cats tend to be very fluid, and to vary with the situation. When cats are crowded, one or more cats may be singled out and treated as outcast by all the other cats. These cats may be killed if there is not enough human intervention. The Cat's Mind is a wonderful book, entertaining and educational.