Differences in the Behavior of Landraces and Breeds of Dogs - Genetics and the Behavior of Domestic Animals - page 209

Sled Dogs
Ecology
Our discussion now jumps to the modern era, and traces the development
of a highly specialized type of dog, the sled dog. While village and
livestock-guarding dogs may date from early Neolithic, sled dogs are rela-
tively recent (historic times), and tandem-harnessed teams are perhaps only
150yearsold( Lantis, 1980 ). The dogs of the Eskimos have little to do
with modern freighting and racing sled dogs. The specialized variety of
these dogs originated in the U.S., Canada, and Asia/Siberia, at the end
of the 19 th century. Their function was moving freight on packed trails, in
tandem harnesses, with a lead dog. Both the initial equipment and the
vocabulary (e.g., “gee,” “haw,” “marche”) of early dog driving was adopted
from French fur trappers, and from horse and ox driving.
Pulling behavior is technically “play” since there is no immediate reward
for the behavior ( Coppinger and Schneider, 1995 ), and it provides the social
facility to perform as a team. Coincidentally, play behavior can reduce inter-
group aggression ( Pellis and Pellis, 1996 ), so it is very important in a dog
team. Lead dogs are not socially defined, but rather are spirited individuals
that can set the pace and take directional commands. They are often females,
or pairs of females, and a team may consist of several lead dogs that can be
rotated into the position during a race.
The behavior of sled dogs is not homologous to adult wolf pack hierarchy
behaviors ( Coppinger and Schneider, 1995 ).
Phenotype
The phenotypic value of sled dogs came in the early 20th century with the
sport of sled dog racing. Since then the shape has steadily changed (evolved).
In the early 20 th century dogs were capable of 5-minute miles for marathon
distances. By mid-century, 4-minute miles was racing speed. By the end of
the century sled dogs were pulling sled and driver in 3-minute miles.
The phenotype of the sled dogs is distinct. In order for the dog to work
(behave) well, the dog must have the proper size and shape ( Coppinger and
Coppinger, 2001; Coppinger and Schneider, 1995 ). Racing dogs weigh
slightly more than 20 kg but less than 27 kg. Maximum size is limited by
surface-to-volume ratio, which determines the heat dispersal capacity during
performance ( Phillips et al., 1981 ). Larger dogs have longer strides. Dogs
with more mass and greater stride can pull more and faster than smaller
dogs, but the detrimental side-effect to greater mass is the inability to radiate
excess heat. This can result very quickly in heat stress problems.
Freight dogs and long-distance racing dogs trot, while racing sled dogs,
in a 20- to 30-mile race, lope. These gaits allow sled dogs to always keep at
least one foot in contact with the ground. Dogs with gaits containing single