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After thousands of years, how did some wolf families become different kinds of dogs?
The Wolf on the Sofa
By Laura McLain Madsen, DVM
Appleseeds, April 2012
As a veterinarian, I treat dogs of all sizes -- from 2-pound Chihuahuas to 200-pound Mastiffs. Think of all the shapes of dogs we see: hotdog Dachshunds, sleek Greyhounds, flat-faced Pugs -- and lots of mixedbreeds.
Every dog -- big or small, shaggy or smooth, solid-colored or spotted -- has wolves in his family tree. Dogsevolvedfrom wolves at least 14,000 years ago, when humans were just learning aboutagricultureand hugemammothsstillroamedNorth America.
Scientists used to think thatancienthumansdeliberatelytamed wolves. But now we are learning that wolves domesticated themselves. (To domesticate an animal means totameit so it will adapt to living with humans.) Imagine a group of people sitting around a fire long ago, cooking meat and telling stories. Wolveslurkin the woods, but only one approaches the humans, who throw her a few scraps of meat. That brave and well-fed wolf then gives birth tocubswho share her friendliness. The cubs, too, stay near the humans who give them food.
Over manygenerations, the friendliest wolves became tame. It wasn't just theirbehaviorthat changed but theirappearancealso.
Over time, humans played a more active role inbreedingthe domesticated wolves. Imagine, for example, that you're a sheepherder back in the time before cars or phones. You need help taking care of your sheep. So, from alitterof puppies, you pick the dog with the strongestinstinctto gather up the flock. Then you breed that dog with other herding dogs. That's how thelivestock-herdingbreeds like Border Collies came to be.
Other breeds developed when humans selected dogs with other useful behaviors: Norwich Terriers for catching rats, Dobermans for guarding the home, Newfoundlands forrescuingpeople in the water, and Cavalier King Charles Spaniels for sitting on laps.
As humansbreddogs for specific reasons, most dogs began to look less and less like wolves. Nevertheless, all dogs aredescendantsof wolves. So, next time you play fetch with your dog, imagine the wolf inside him!
After thousands of years, how did some wolf families become different kinds of dogs?
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Write your essay answer here.
Use this as your first sentence:
After thousands of years, some wolf families evolved into different kinds of dogs.