Many young animals are miniatures of their parents: the kitten is a small cat, the foal a small horse, the chick a small hen. Growing up, for them, means getting bigger and stronger — the body’s shape stays the same.
Examples
Example 8.5 (Kitten to cat)
The newborn kitten drinks milk with closed eyes. At one month it plays and pounces; at six months it hunts like a grown cat; at one year it is an adult, perhaps with kittens of its own. Small cat, bigger cat, cat: the same shape all along the way.