Biology Reference
In-Depth Information
bite” dogs are represented by many breeds, often bred specifically to work
with a particular class of livestock, e.g., with sheep (border collies) or cattle
(Queensland blue heelers). There are also subcategories based on whether
the livestock are to be gathered and penned (the dogs are “headers”), or
driven (“heelers”), or captured (“catch dogs”). Within each of these catego-
ries, some breeds operate close to the handler, others at great distances
without much contact (e.g., New Zealand huntaways). Some breeds vocalize
while working (Australian shepherds); others are silent (border collies). Each
behavior is specific to the breed, and it is inappropriate, counterproductive,
and perhaps impossible, for example, to use cattle heeling dogs to pen sheep.
Working performance is based on the display of one or more specific
motor patterns, which the handler directs by commanding the direction of
display with whistles, vocalizations, or hand signals ( McConnell and Baylis,
1985 ). The “chase” motor pattern is universal, but some dogs are expected
to precede the chase with an eye-stalk behavior. Cattle heelers are
expected to chase and grab-bite (nip at the heels), but the grab-bite is a fault
in sheep dogs.
The presence, absence, frequency, or sequencing of the display of each of
these motor patterns differentiates the breeds of herding dogs. Each herding
breed shows one or more of these motor patterns and the form is usually
unique. For example, the orientation of the outrun can be a direct pursuit, as
in the heelers, driving the animals away from the handler, or a circling orien-
tation, as in the headers, where the dog works 180 from the handler and
moves the sheep toward the handler. Different strains of border collies dis-
play different outruns, which are locally popular because of management
practices.
Like herding dogs, gun dogs have breed-specific motor patterns.
Retrievers have the spontaneous onset of “chase and retrieve.” Early in
development a pup appears with an object in its mouth, and to throw it guar-
antees the owner a lifetime of repetitive performance. Grab-bites are part of
the retrieving behavior, but crush or kill-bites are faults known as “hard
mouth.” Dissect and eat motor patterns are, obviously, disqualifications.
Pointers silently hold the eye-stalk behavior until commanded otherwise.
Foxhounds and coonhounds are expected to vocalize while chasing (called
“voice”) and are expected to grab and kill-bite.
Phenotype
Some herding dogs have unique morphological traits. Cattle dogs such as
blue heelers and corgis have shorter legs, ostensibly so a kicking cow's hoof
passes over their head. Since sheep do not kick, sheep dogs are not short-
legged. In fact, herding dog handlers rarely talk about morphology, in
contrast to sled dog drivers, who never give up on the subject. However,
complaints about herding dogs not having endurance, or being uncontrollable
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