discusses the evolution and remarkable diversity of dogs.
notes that there are currently more than 400 different breeds of dogs
relates two competing theories about how dogs were domesticated: Stone
Age humans adopted and selectively bred wolves for tameness; wolves essentially
"chose" domestication when they began to forage for food near prehistoric
dumps. There, tameness was an advantage.
considers why dogs have tails that stick up, droopy ears, and other
traits that are not found in the wolf gene pool.
recounts an experiment in which foxes bred for tameness produced dog-like
traits, leading to speculation that the new traits were due to different levels
of hormones created as a byproduct of tameness.
explores how dominance hierarchies in wolf society have contributed to
making dogs well suited to be pets.
suggests that dogs specialized in specific behaviors—hunting,
tracking, pointing, retrieving—and that over thousands of years humans
used food to reward the dogs best at these behaviors. These better-fed dogs
then had an improved chance at surviving and passing on their genes.
proposes a theory that the diversity found in dogs is due to subtle
changes in the regulatory DNA that instructs when a gene turns on and off.
suggests that dogs' remarkable ability to adapt to different environments
is due to an extended critical period of social development.
reviews the problem of genetic diseases due to extensive inbreeding.