The following article explores
the idea that the reason having a dog lowers high blood pressure,
reduces anxiety and stress, and improves a person's general health
is that humans and dogs have evolved together. If you're looking
for a stress management technique, if you're looking to reduce
blood pressure of find stress relief, you would be hard-pressed
to find a more enjoyable solution than getting a dog.
EARLY ONE MORNING, Pearl Carlson of Granite
Falls, Washington, woke up because her dog was trying to pull
her off the bed. The house was on fire.
The dog saved the lives of Pearl and her
parents that morning. The most amazing thing was what they discovered
afterwards: The dog had splinters in his mouth because when the
fire started, the dog was outside. He chewed his way through
a plywood door to get into the burning house to save his family.
He got burned pretty badly. The chain around his neck got so
hot it burned his throat, making it impossible for him to bark.
We've heard true stories like this before
dogs saving people and people saving dogs. The two species
have a great fondness for each other. This fondness has deep
Dogs and people evolved together. We formed
a symbiotic relationship long ago and became a kind of superpredator.
A symbiotic relationship means two species
are better off together than they are apart, that they contribute
to each others' ability to survive. Lichen is a good example.
Lichen (that yellow and orange stuff that grows on rocks) isn't
one species, but two. It is a symbiotic relationship between
a fungus and an alga. The fungus provides a protective scaffolding
on which the alga can grow, and the alga provides a specific
carbohydrate the fungus lives on.
Two species living together in such close
association tend to effect each other. The presence of one will
effect the evolutionary adaptations of the other.
A group of humans in a partnership with
dogs would survive better than a group of humans without dogs
in our prehistoric past.
When our relationship began, our ancestors
and our dogs' ancestors (wolves) ate similar foods and both species
hunted in groups. Both species are extremely social and survive
by cooperating with each other. But each species has different
strengths. Wolves are good at chasing large animals but not as
good at killing them. Sometimes they'll corner a large animal,
like a moose, and try for several days before they manage to
kill it. The human-dog superpredator was able to kill animals
that either species by itself would find difficult or impossible
to kill. Both dogs and humans ate more if the dogs could corner
prey and humans could kill it.
"With its speed and tracking ability,"
wrote Michael W. Fox, "the dog was an ally in the hunt,
and it kept us warm at night with its higher body temperature
and was protector and playmate for our children."
The two species fill each others' gaps.
Dogs don't see as well as humans. People see more color and detail.
A tremendous amount of the human brain is devoted to vision.
But dogs have much better peripheral vision and they are considerably
more capable of perceiving movement than people are.
Dogs can hear much higher frequencies that
humans. A dog's brain has twenty times more olfactory neurons
than a human brain. Donald McCaig wrote, "Since dogs could
hear and smell better than men, we could concentrate on sight."
And even our tastes complemented each other
well. Animal behaviorist Dennis Fetko points out that humans
usually ate the meat and fat, "while throwing away the very
things wolves craved bones, offal, fur, horns and hoofs."
"By tapping wolves' protective, territorial
instincts," wrote Lowell Ponte, "our ancestors acquired
watchdogs. Other predators such as bears tended to avoid them."
While we were selectively breeding wolves
to produce characteristics we wanted, their skills and companionship
may have allowed us to evolve in certain ways. We didn't need
to rely so much on our sense of smell, for example.
The combination of dog and human creates
a superspecies with greatly expanded powers. This superspecies
can hear very high frequencies, see great detail in color, detect
movement extremely well, and has great peripheral vision. This
superpredator can detect the faintest odor in the air of enemy
or foodsource and has the endurance and speed to chase down any
prey and the ability to make weapons that will kill any prey.
We have benefited greatly from our alliance
with dogs. And they also gained benefits. Dogs have nearly twice
the life-span of wolves in the wild.
There might have been a kind of selection
for humans who liked dogs. It is entirely possible that we have
evolved to enjoy the company of dogs. That may be why dogs have
a good effect on our health and moods. It may be why merely petting
a dog lowers a person's blood-pressure and general anxiety level.
Whatever the explanation, most people respond to dogs, particularly
their own dog, with a general lowering of anxiety.
Researchers at Cambridge University found
that after getting a dog, a person's general health improves.
"Dogs help us psychologically," writes Toyoharu Kojima,
author of Legacy of the Dog. "Tests have shown
that walking a dog, or just having one as a companion, effectively
helps speed recovery from an illness and aid in rehabilitative
UCLA researcher Judith Siegel studied a
thousand elderly people. Those who owned a dog required twenty
percent less medical care than people without a pet.
So here is an anxiety-lowering and stress-reducing
method that may not have occurred to you: Get a dog.
Learn other ways of lowering your stress
or anxiety: Reduce Stress
A good DVD on the latest dog research is
Nova's Dogs Decoded.