Differences in the Behavior of Landraces and Breeds of Dogs - Genetics and the Behavior of Domestic Animals - page 207

Dogs and other canids develop their social repertoire during a critical
period ( Fox and Bekoff, 1975; Scott and Fuller, 1965; Scott and Marston,
1950 ). This period (sometimes called the sensitive period; Bateson, 1979;
Estep, 1996 ) for social development in dogs is thought to occur between
approximately 4 and 14 weeks of age. Dogs that do not have close interspe-
cific interaction with people or livestock during this time develop shyness,
a behavior similar to if not identical to village dog behavior. Shyness is
a heritable characteristic in dogs ( Willis, 1995 ).
Developmentally, individuals pass through several sensitive periods with
the onset of genetically programmed motor patterns. Animals develop their
species (breed)-typical behavior repertoire during these periods of receptivity
and “learn” where and when to display the motor pattern. As they pass out
of a stage, their chances of learning the associative behaviors become
increasingly diminished, if not impossible. If the proper environment is
not present during that period, then the resulting behavior cannot become
functional.
Thus, village dogs, on their way to specialization, can display three dis-
tinct (innate?) behavioral repertoires depending on their developmental envi-
ronment. (1) Dogs born in and around villages, with social contact limited
almost exclusively to other dogs, display shy behavior with humans and
livestock. (2) Dogs raised in proximity to humans are not shy with them,
but are attentive, perhaps following them on hunting and gathering forays.
(3) Animals raised in proximity to livestock are attentive to them, following
them on their daily foraging activities.
In each case dogs will display their “dog” social motor patterns to the
species of primary contact during the sensitive period and to a lesser extent
to the other two, which are also present in the pastoral environment. There is
no genetic difference among the three behaviorally distinct types (village
dogs, livestock-guarding dogs, or pets) and indeed in many areas of the
world they are phenotypically indistinguishable ( Coppinger and Coppinger,
2001 ).
Good livestock-guarding dogs do not display predatory motor patterns to
sheep, because of their early social bonding. However, although some do
show chase and bite behaviors even if they are raised with livestock, most
do not display these patterns even if they are not raised with livestock,
suggesting that these motor patterns are heritable and responsive to selective
forces.
Unfortunately, our knowledge of the details of critical-period develop-
ment is incomplete for the dog, and whether specific breeds such as
livestock-guarding dogs have lost predatory inclinations is suspected but
not proven ( Coppinger et al., 1987 ). Not only do they not display preda-
tory behaviors even when not raised with livestock, but even those raised
as pets commonly do not chase a ball. Biological mechanisms for the
diversification of village dogs into breeds, whether they be hunting dogs