پنجشنبه ۲۲ شهریور ۰۳ | ۲۲:۴۳ ۸ بازديد
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Canines are one of the most exciting groups of mammals on our planet. They
come and go on the evolutionary stage, both in terms of time and space. At
the start of the twenty-first century, at a range of locations across the Northern
Hemisphere, wolves were on the brink of extinction. Now, they are back in many
countries across Europe and also in the United States. However, life is never the
same—evolution cannot repeat itself. These modern wolves also hybridize with
coyotes and free-ranging dogs, possibly giving way to new forms of canine. In
Europe, hunters had not seen the golden jackal for a century, but now, within
the last ten years, jackals have reconquered old territories and ventured into
new ones. Some of them have been reported hunting in the north of Europe,
close to the Baltic Sea.
The existence of dogs and their many varieties is one of the most
extraordinary proofs for evolution. Charles Darwin himself referred to domestic
animals and especially to dogs when citing animal examples of evolution.
However, as change is part of evolution, we should not expect the variation we
have in our dogs today to stay with us forever. New times and new challenges
may prompt the evolution of new creatures, and dogs are no exception.
While mutual friendship between dogs and humans may exist in billions of
households around the world, in many situations we still want to be in charge.
Humans can be quite a nuisance in this respect. One such case is dog breeding.
Reproduction is a key to the evolution of a species, and any major failure can
have fatal consequences in the long run. Especially in the case of purebred dogs,
which are close to the hearts of many people, present breeding practices need to
Below Despite having
been domesticated, dogs
often remind us of their
wild relatives.© Copyright, Princeton University Press. No part of this book may be
distributed, posted, or reproduced in any form by digital or mechanical
means without prior written permission of the publisher.For general queries, contact webmaster@press.princeton.edu
males or the “perfect” champion male is advantageous for any breed. It may
lead to a fatally reduced breeding population, the increase of inbreeding, and
the emergence of physical malformations, illnesses, and behavioral problems.
As so many of us now live in cities, dogs may be one of our few connections
to nature, so we should make every effort to keep them as healthy as possible
and offer them the best life while allowing them to express their full biological
potential. Dogs should be kept as companions only if the owner has the time
and devotion to allow them the freedom of being a dog in addition to being a
member of a family or other social community of humans. In this sense, dogs
should be seen as the “wolves of the cities”—independent whether they are
big or small, like to bark, or roam free in our green spaces.
Let’s allow dogs to work if they enjoy it. People may or may not like to
work, but dogs are different. They have been selected to like working with
people, participating in joint activities. Research has also shown that many dogs
are keen to work for people’s “love,” social feedback, and for the feeling that they
are part of the family. As well as being genetic, as in the case of working breeds,
this tendency can be facilitated through dog training. Thus, a well-trained dog,
which has been chosen for this task, enjoys interacting with its owner. They
would probably suffer if they were prevented from doing so. For dogs, working
is closer to some kind of social engagement than a form of hard labor. In
exchange, people express their feelings toward their dogs. But we should be
careful not to demand too much; dogs also deserve to be dogs.© Copyright, Princeton University Press. No part of this book may be
distributed, posted, or reproduced in any form by digital or mechanical
means without prior written permission of the publisher.For general queries, contact webmaster@press.princeton.edu
distributed, posted, or reproduced in any form by digital or mechanical
means without prior written permission of the publisher.For general queries, contact webmaster@press.princeton.edu
In this book, we hope to show you the dog from many different perspectives.
Dogs are descendants of extinct wolflike canines, so they share many features
with their wild cousins. Dogs also have a long and specific history with humans,
and generations of dogs have witnessed how our societies have changed in the
last 3,000–4,000 years. And, despite the fact that our relationship with dogs has
become more intimate in some ways, dogs still remain dogs, in a good sense. So,
we need to know about their biology: how they see, hear, and smell, and how they
interact with one other and with humans, showing a wide array of sophisticated
behavioral signals for communication. Dog owners have to become aware of the
mental abilities of their companions in order to provide them with the necessary
challenges to keep their minds sharp and active. This also ensures that dogs have
a good quality of life during aging, as a more experienced and skillful dog has a
lower chance of showing cognitive decline when it gets older.
Knowing about the development of dogs as puppies is crucial because this is
the time when dog owners and breeders can have a huge influence on the future
character of the dog. In sharp contrast to humans, who develop for around 18
years, in dogs maturation is much shorter, only one to two years. What a young
dog may learn spontaneously after a few incidents may take much longer for an
adult dog to acquire. Puppies learn as soon they are born, and if something is
learned early, this can be remembered for their whole life.
And what about our future with dogs? In recent years, our societies have been
changing at a rocketing speed. So far, dogs have been an exceptional means of
providing us with a unique experience of friendship but now there are new
competitors on the horizon. Television, the internet, and cell phones are giving
many people, especially the young, the sense of being members of a community
and there seems to be less time for developing human–canine relationships within
the home. In the industrialized countries, the population of family dog numbers
is stagnating or on the decrease—is this a sign of a relationship in decline?
Who can tell the future? But, for sure, humans have some responsibility for
their creatures. The future of dogs lies in their behavioral flexibility, their ability
to adapt to the newly emerging human needs in modern society. The new roles
dogs play in our society give rise to new challenges for both dogs and dog
trainers. We all have to make sure that dogs’ needs are met, so they will continue
to give us their company for centuries to come.
We hope that this book, which includes some of the newest insights from
dog science, will help you, the reader, to respect your companion even more, or
encourage you to find one of these wonderful partners to share your life with.
11INTRODUCING THE DOG
Below Dogs, especially
those living in cities, need
a lot of exercise to have
a good quality of life.© Copyright, Princeton University Press. No part of this book may be
distributed, posted, or reproduced in any form by digital or mechanical
means without prior written permission of the publisher.For general queries, contact webmaster@press.princeton.edu
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Evolution & Ecology© Copyright, Princeton University Press. No part of this book may be
distributed, posted, or reproduced in any form by digital or mechanical
means without prior written permission of the publisher.For general queries, contact webmaster@press.princeton.edu
There is a rather striking resemblance
between the appearance of any extant
member of family Canidae (the group of
carnivores closely related to and including
dogs) and the long-ago extinct Miacis, the
common ancestor of terrestrial predators.
Thus, the Canidae show ancient
anatomical features, or rather they are
similar to the ancient form. This does
not mean that the shape and functions
of dogs and their closest relatives are
obsolete—the high number of species still
existing testifies just the opposite: The
ancient form is still successful.
ORIGINS ON THE
AMERICAN CONTINENT
The history of carnivorous mammals
started about 55 million years ago (mya),
not so long after the last of the great
dinosaurs had disappeared at the end
of the Cretaceous. Interestingly, Miacis
emerged in North America—and the
larger part of the evolution of Canidae
also happened there. In the Paleocene
(about 50 mya) the two main divisions of
carnivores diverged, forming the catlike
feliforms and the wolflike caniforms.
Toward the end of the Paleocene,
about 34 mya, the Caninae subfamily
appeared, and this would become the
Above The Miacis,
a primitive carnivore,
populated both Eurasia
and the North American
continent about 55-33
million years ago.
Animals like this were
the ancestors of extant
canids, bears, and
weasels.
Right Canids can look
considerably different. The
maned wolf is the tallest of all
(3 feet/0.9 m at the withers).
The stocky bush dog is no bigger
than a dachshund. Both live in
South America.
Maned wolf
Bush dog
Miacis
only surviving subfamily of the
Canidae—and the ancestor of all the
extant species of foxes, jackals, and
wolves. The secret for their success may
be that they were not overtly restricted
to the hypercarnivorous (“meat only”)
diet of other subfamilies, which became
extinct because of their narrow ecological
tolerance of environmental changes.
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