How did reptiles start to regulate their body temperature and get a perspiratory mechanism which would allow it to maintain its body temperature? Is it possible they replaced their scales with fur or hair and started to secrete milk? In order for the theory of evolution ...to explain the origin of mammals,these questions. must be answered scientifically by evolutionary theory .
BUT evolutionary sources only provide just so imaginitive and unscientific ideas .
Some of the reptiles in the colder regions began to develop a method of keeping their bodies warm. Their heat output increased when it was cold and their heat loss was cut down when scales became smaller and more pointed, and evolved into fur. Sweating was also an adaptation to regulate the body temperature, a device to cool the body when necessary by evaporation of water. But incidentally the young of these reptiles began to lick the sweat of the mother for nourishment. Certain sweat glands began to secrete a richer and richer secretion, which eventually became milk. Thus the young of these early mammals had a better start in life .
George Gamow, Martynas Ycas, Mr. Tompkins Inside Himself, The Viking Press, New York, 1967, p. 149
That is funny , the production of a highly complex nutrient such as milk can be attributed to a living creature licking its mother's body sweat.
Once upon a time ..............................MILK .