Chief among the qualities that unite our domestic minions is a trend known as Pedomorphosis, which occurs when adult organisms retain traits that are usually found only in their young. The adorable apple heads of chihuahuas are an example of such a physical trait. Pedomorphosis can also apply to behavior, as well. In fact, the physical pedomorphic traits are primarily the result of selection for desired juvenile behaviors. As it turns out, the genes that control behavior are closely linked to those that shape anatomy.
As a result, selecting playful, docile, adaptable and friendly behaviors in the animals we bred over thousands of years has dragged along a host of physical traits as well. Floppy ears, round heads, large eyes, colorful coats and curly or shortened tails are pedomorphic traits that many or most domestic animal share.
We even see pedomorphic behaviors and physical features in human beings, begging the question did humans evolve by domesticating themselves?
The traits we love (and share with) our dogs are easy to understand. They remain playful even into old age; they have endearing youthful features that elicit our basic instincts to mother them incessantly; They submit to us readily and follow us like little pups. As a result, we find dogs trustworthy and loyal companions, despite that their closest kin, the wolves, present a serious danger in close quarters.
The same can be said of our many other domestic friends. Selection for desirable, juvenile behaviors necessary for our coexistence results in juvenile traits that alter their physical appearances and make man-made varieties obviously different from their wild cousins.
But what of our feline friends? Surely they have been thoroughly changed as well. It appears that the benefits of Artificial Selection have been exacted to a lesser degree in cats. Cats show few if any pedomorphic behaviors, and many a new cat owner has lamented that the cute, friendly, playful kitten they obtained is now a sleek, aloof and lazy adult cat. So it would seem that cats may have stubbornly refused to follow the typical road to life with human beings.
This brings us to a final question to ponder: Why do we keep cats at all? If humans have not wielded the tools of Artificial Selection to perfect the feline according to our standards, how is it that cats have become more popular than the variety of domestic dogs, each of which has been meticulously sculpted to fulfill a specific role in our busy lives?
Have cats somehow escaped our notice and thus our genetic tampering? Or were cats, even in their wild state, simply right for niche they fill? My answer to this question will be revealed in tomorrow's blog entry. And we'll see that their successful invasion of our homes relies on three simple traits and a whole lot of charm.
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