Why Dogs Are So Physically Diverse
Nurture and Nature are Responsible for Variety in Canine Appearance
Not only do dogs come in an amazing assortment of sizes, shapes, and colors; there's also a logical explanation about why they can mate with wolves and coyotes.
Have you ever wondered how an animal can appear as a plush, heavy-shedding Alaskan Malamute or a hairless Chinese Crested or a mop-coated Komondor or a barkless Basenji and still be the same species? Within this mysterious biology lies answers to many questions we’ve asked about our companion animals for generations.
However, believe it or not, shaving any dog down to its skin (not recommended) will reveal a basically similar structure in spite of great differences in size, coat type, eye color, ear style and carriage, and more. Only the minutest difference at the genetic level separates the statuesque Afghan Hound from the short-legged Dachshund.
The domestic dog’s Latin name is canis familaris. The generic canis denotes the dentition it shares with its cousins, which include the wolves, foxes, and jackals. Familaris refers to the characteristic eye structure which lacks the slit pupils of its feral cousins.
Since the domestic dog, like the canis lupus (wolf) and the canis latrans (coyote), has a total of 78 chromosomes; it is biologically possible for these species to interbreed.
A dog possesses 32 chromosomes more than a human being’s 46. This high number of chromosomes accounts for the amazing physical diversity throughout dogdom as contrasted with the relative homogeneity among people.
In The Book of All Terriers, John T. Marvin offers a Darwinian explanation as to how individual breeds came about: “A breed, like a dialect of language, can hardly be said to have a distinct origin. A man preserves and breeds from an individual with some slight deviation of structure, or takes more care than usual in mating his best animals and thus improves them, and the improved animals slowly spread in the immediate neighborhood. . .
"As soon as the points of value are once acknowledged, the principle, as I have called it, of unconscious selection will always tend—perhaps more at one period than at another according to the state of civilization of the inhabitants—slowly to add to the characteristic features of the breed whatever it may be.
Add the twist and turns of evolution and adaptation to this cauldron of diversification, and you find dogs in all shapes and sizes. The world’s many terrains, climates-- and human selection-- influenced which dogs would acquiesce to become man’s--and woman’s-- first and arguably only truly mutual companion animal.
Where does the word "dog" come from? Although the origin of the word "dog" remains murky, etymologists have some theories.
The Old English word for dog,dogca, emerged in the 13th century. It replaced the commonly used hund, a word rooted in an Indo-European word kuntos. This supports the theory that dogs were part of human life during the earliest days of spoken language. Kuntosbecame the Greek word kyon, the root of the word cynic . A group of ancient Greek philosophers were so-named for their "dog-like" sneering at others' weaknesses. From the Latin word for dog, canis derives "canine"-- and also "kennel" and "canary." Apparently those musically gifted yellow birds were named for the large breed pf brown or brindle dogs indigenous to the Canary Islands.
Sources
Hendrickson, Robert, The Facts on File Encyclopedia of Word and Phrase Origins (New York: Facts on File, 1997).
Marvin, John T., The Book of All Terriers (New York: Howell Book House, 1979).
