Prof. Dr. Martin S. Fischer, Institute of Special Zoology and Evolutionary Biology
with the Phyletisches Museum, Friedrich-Schiller University in Jena
The domestication of the wolf has led to an astonishing diversity of dog breeds
in terms of size, weight, physique and general appearance. The reasons for the greatest
diversity among all pets lie in the variability inherent in wolves as well as the
consequences of the thousands of years of artificial selection. With the world’s
most extensive study so far on the locomotion of dogs, in which 327 dogs were examined
from 32 breeds, we investigated the question of whether similar variability can
be found in the movement of the different breeds of dog and, in particular, under
the influence of a 40-fold difference in weight between a Chihuahua or Dachshund
and a Mastiff of whether the dogs move in extensively the same manner irrespective
of breed.
The result is surprising insofar as the differences between ten dogs of one breed
are almost always greater than between the breeds. Contrary to our expectations,
the movement of dogs has thus changed only little over the long history of their
domestication. The relative lengths in particular, i.e. the proportions of the individual
sections of the limbs, have changed to a smaller extent than expected in the breeds
and, above all, the relative length of the upper arm is the same for all breeds
within one percent. If the proportions are so similar, it is then immediately clear
that the movement pattern must also be very similar. In fact, too much attention
has been paid to minor or only putative changes while the major features they have
in common have been overlooked.
For example, if we compare the length of stride – with the height of the withers
as the standard – of the Dachshund and the Mastiff, this is 1.3 for the Dachshund
and 1.2 for the Mastiff at the front when walking and 1.9 and 1.8 respectively at
the trot. The corresponding values at the rear are 1.6 and 2.1 for the Dachshund,
with 1.4 and 2.0 for the Mastiff. The Mastiff reaches further forward when walking
with an almost identical length of stride on the front limb, while the Dachshund
has a greater length of stride, though the two breeds behave almost identically
at the rear. We calculated that the turn of the shoulder blade accounts for around
two thirds of the length of stride at the front for all dogs. So it is not surprising
that the effective amplitude (raising-lowering differential) for the two breeds
amounts to 34° for the Dachshund when walking and 39° at the trot, with values of
37° and 44° respectively for the Mastiff. The pattern of movement is thus very similar
for both breeds. Probably the most important finding of the study is the fact that
dogs have retained the wolf-like nature of their motion.
We have presented the results of the study in a book entitled “Dogs in motion”,
in which we also give an extensive portrayal of current knowledge concerning the
locomotion of dogs. We have reappraised the most important results of 300 scientific
studies in both words and pictures in such a way that every interested reader can
also obtain extensive information about bones, muscles, joints, as well as overall
motion and the dynamic aspects occurring in this regard. With a unique visual language
presentation and DVD with more than 300 film clips (high-speed videos, high-speed
X-ray films and, in particular, 3D animations), we hope we have opened the door
to a new understanding of the movement of our dogs.
Link to the video (in German)
http://www.fci.be/symposium2011/mfischer.html
(recorded on November 11th, 2011, on the occasion of the FCI Cynological Days organised
to celebrate FCI’s Centenary).