When pups are born they are little more than blobs. Muscles and their nerve connections are only in the process of forming so coordination is poor, and that's overstated. The pup can crawl. The direction is toward its mom and her nipples. Olfaction, the sense of smell, leads the pup in the right direction and the lips, nose, mouth area in general, touch a nipple and lips, tongue and their associated musculature react reflexively to produce the sucking response. Not a lot of brain work going on there. Sucking is a reflex with no conscious effort or thought involved in it. It's an involuntary act that functions with only rudimentary neural development and little or no brain involvement.

Gradually muscles and nerves become better organized, coordination improving concomitantly. With practice the sucking reflex improves, becomes more efficient, the pup's crawling becomes more directed even though front and hind feet are not usually in synch. By three to four weeks the synchrony improves to the point that the pup can walk.

At first there are mistakes, pup may stumble, trip over nothing, get one foot or two moving at the wrong time, a klutz. Nothing like the elegant bird finder one would hope for. Even at four months, many pups are still gawky, ungainly, and foot plopping clumsy. The road from the four-week-old stumbler to finished elegance is paved with practice, pushing the muscles and their associated nerves to never fail myoneural connections and strengthened muscles with lightning speed and totally smooth contractions. But the pup can't do this all alone; it needs help from its dam. It needs even more help from the breeder because only the breeder can control the environment in which the pup grows up.

Borrowing the adage–-if you don't use it you lose it–-and paraphrasing it to make it applicable to developing pups, we can say--if you don't use it, you won't ever have it to lose. More than forty years ago physiological psychologists, the only people working on behavior of animals in North America at the time and that only for application to human behavior, performed all sorts of experiments on rats, cats and to a small extent on dogs, to demonstrate both the old adage and the revamped version. These experiments ran the gamut from immobilizing a limb of a young animal from weaning to adulthood, patching an eye from birth, to single muscle denervation, to partial brain ablation.

The effect on muscle development in all these experiments, and there were hundreds of them, was the atrophy you would expect but the effect on nerve and brain development was not predicted. Immobilization of a limb also prevented the formation of neural connections and the portion of the brain that dealt with the limb that was immobilized was smaller and had far fewer nerve cells present than the normal contra lateral leg.