Breed Story - Cairn Terrier

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Canis lupus

Then the Woman picked up a roasted mutton-bone and threw it to Wild Dog, and said, "Wild Thing out of the Wild Woods, taste and try." Wild Dog gnawed the bone, and it was more delicious than anything he had ever tasted, and he said, "O my Enemy and Wife of my Enemy, give me another."

The Woman said, "Wild Thing out of the Wild Woods, help my Man to hunt through the day and guard this Cave at night, and I will give you as many roast bones as you need."

— Rudyard Kipling, Just So Stories

Canis familiaris

The dog is the product of 100,000 years of evolution from its ancestor, the wolf (whose fossils go back two million years). Outwardly, this evolutionary change is enormous. Consider how different a wolf and a Cairn Terrier look! Such a tremendous change in such a short time comes from artificial, rather than natural, selection. Humankind is the dog's creator, for the human hand has guided the dog's evolution.

Nature teems with intimate relationships between species, but no relationship is so deep and wondrous as the relationship between the human and the dog. Considering that dogs started as wolves — natural enemies — how could this relationship have come about?

The wolf is the evolutionary ancestor of the dog.

Association between humans and wolves began around 400,000 years ago. Then, humans did not yet farm; they migrated in small hunting-and-gathering clans. Much like wolves, except that we call a clan of wolves a "pack." Both species hunted similar prey in a similar, cooperative way.

Also, both societies have similar structure and rules. As among social insects, political correctness is determined by the net transmission of memes till the social "wind" in one direction prevails and the vote suddenly becomes unanimous. Nonconformity is punished by exclusion from the group. There is a pecking order, ganging-up, and power struggles, such as we see on "reality TV." So wolves had hard-wired behavior ideal for relating to humans.

The catalyst that brought about this unlikely alliance was fire. Wolves who tasted cooked food would, of course, do anything for more. So campfire attracted them. As pack hunters, they feared no adversary and were quite likely to prey on children or lone humans, so they were braver than other animals about approaching human campfires and lurking in the shadows.

It is easy to imagine the various approaches wolves would try, especially when food was scarce. It is also easy to imagine humans rewarding certain non-violent approaches by accepting smaller, less threatening wolves who approached humans humbly — that is, as wolves approach the alpha wolf in their pack. Indeed, humans can't resist coaxing wild animals with food! Doing this amounted to teaching wolves a dog's chief talent — to beg.

Whenever possible, wolves would steal a clan's kill, or humans would steal a pack's kill. Like many species, both probably learned to follow the hunting parties of the other. Such robbery is common in nature, but human intelligence knew how to use this tool to manipulate the wolf: by cooking and sharing the spoils, humans made themselves leaders of the pack, instituting cooperation in hunting that was advantageous to both species.

Note that Rudyard Kipling attributes the domestication of the wolf to Woman, not Man. To persuasion, not dominance. A testament to the power of begging, this relationship between human and wolf-dog was a match made in heaven, for both species profited and survived in greater numbers as a result. And of course the offspring of these accepted wolves tended to be like them — smaller, less threatening, more tame — whereas in the wild population, nature was still selecting for the opposite characteristics.

The relationship gradually grew more intimate. By feeding the most acceptable wolves and killing or driving off the others, humans began the creation of a new species. Over time, this population of wolves living with humans changed into the prototype of the modern dog. This animal was smaller than the wolf and had a shorter snout. It was similar to the medium-sized pariah dogs feeding in garbage dumps around cities worldwide. Egyptian art of the fourth millennium B.C. depicts dogs hunting with humans by driving prey into nets. The oldest fossils of humans and dogs together — such as graves in which the deceased cradles a puppy — are about 14,000 years old.

Human direction of the dog's evolution has speeded and enhanced it. Moreover, wolves and dogs have 76 chromosomes, a relatively large number. (Humans have 46.) This arrangement of genes allows for much more variety through a vastly enhanced potential for recombination. As a result, no other species shows such diversity as the dog. In fact, selective breeding by humans has pushed the envelope so far that dogs break the rule that all members of a species can naturally interbreed. Sheer size difference prevents the smallest races of dogs from naturally interbreeding with the largest. Their genes match up perfectly though. Moreover, their sperm and eggs combine to form normal dog embryos that can be implanted in the uterus of suitably sized female and develop into a normal, fertile adult dog. (Not so when you cross separate species, for when offspring do result, they are infertile because their chromosomes do not match up properly.)

Yet this apparent diversity is misleading. At the molecular level, dogs and wolves are almost identical! Genetically, they are similar as humans of different races. The widely varying appearance of dog breeds is due mainly to the timing of genetic switches that merely trigger growth in certain parts of the dog embryo at certain times.

© 2002 - 2007, Kathy Krajco - all rights reserved.
The URL of this Web page is http://www.cairn-terrier.operationdoubles.com/evolution_of_dogs.htm
It was last updated on 10/27/2007.
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