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The dog (Canis lupus familiaris) is a domesticated
subspecies of the wolf, a mammal of the Canidae
family of the order Carnivora. The term encompasses
both feral and pet varieties and is also sometimes
used to describe wild canids of other subspecies
or species. The domestic dog has been (and continues
to be) one of the most widely-kept working and companion
animals in human history, as well as being a food
source in some cultures. There are estimated to
be 400 million dogs in the world.
The dog has developed into hundreds of varied breeds.
Height measured to the withers ranges from a few
inches in the Chihuahua to a few feet in the Great
Dane; color varies from white through grays (usually
called blue) to black, and browns from light (tan)
to dark ("red" or "chocolate") in a wide variation
of patterns; and, coats can be very short to many
centimeters long, from coarse hair to something
akin to wool, straight or curly, or smooth.
Dog Origin
Based on DNA evidence, the wolf ancestors of
modern dogs diverged from other wolves about 100,000
years ago, and dogs were domesticated from those
wolf ancestors about 15,000 years ago. This date
would make dogs the first species to be domesticated
by humans. Evidence suggests that dogs were first
domesticated in East Asia, possibly China, and some
of the peoples who entered North America took dogs
with them from Asia.
As humans migrated around the planet a variety
of dog forms migrated with them. The agricultural
revolution and subsequent urban revolution led to
an increase in the dog population and a demand for
specialization. These circumstances would provide
the opportunity for selective breeding to create
specialized working dogs and pets.
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