Information on the history of dogs
from it's early ancestors until present

Evolution: From early canids to today's dogs


Canines -- defined!
All dogs -- wild and domestic, extinct and living -- belong to
the canid family (family Canidę). Canids have been around a long
time and are the earliest known carnivores (order Carnivora.)

In fact, dogs first appeared in the fossil record about 40 million
years ago, well before other carnivore families like cats or bears.
Dogs and most other carnivores have a pair of blade-like teeth
called the carnassials (car NAS ee uhls) in their upper and lower
jaws. These teeth work like scissors to slice through muscle and skin.

Modern canines number several dozen species


The canid family tree includes 35 living species. Though there
are a few lone lineages, there are three main groups:

South American zorros (foxes)
Wolf-like canines, including the coyote, jackals, wolves, and dogs
Fox-like canines, including the red fox and its relatives
The domestic dog's closest kin is the gray wolf (Canis lupus).
 

From wolf to dog

Fossil and genetic evidence confirms that all dogs are the descendants
of wolves. In fact, skeletons of the earliest dogs and their wild wolf
cousins can be tough to tell apart. Some of the key differences
that scientists look for are:
Dog skulls often have a more prominent "stop" (the break in the
downward slope from the forehead to the tip of the nose).
Dogs' teeth are squatter than those of similar-sized wolves.

All of the nearly 400 domestic dog breeds belong to a single s
pecies, Canis familiaris.

A species is a group of individuals that can successfully reproduce
with one another. A breed is a sub-group of domestic animals
whose looks and behavior have been shaped by human selection.
All breeds within a species can potentially reproduce with each
other, but the distinctive features of breeds can be lost when one
breed is crossed with another.

Many dogs have already become extinct.
Dogs have been around for millions of years. The fossil record shows
three main groups of dogs.

Hesperocyon

The first group evolved in North America about 40 million years
ago. Fossil evidence tells us that these first dogs looked like a cross
between a weasel and fox. The name Hesperocyon (hess pur oh
SYE on) means "western dog." The hesperocyonines became
extinct about 15 million years ago.

 

Epicyon

The second group, the borophagines (bohr oh FAY jeens), began
flourishing about 34 million years ago and were larger hyena-like
animals with huge jaw muscles and sturdy teeth. They became
extinct about 2.5 million years ago.

 

Wolf

The third group, the canines (KAY nines), includes the extinct
dire wolf and all living species of canines. This group occurred
only in North America until about 7 million years ago, when some
species crossed a land bridge to Asia.

From: National History Museum of Los Angeles County

Select Me for more information on the history of wolves to dogs

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