Behavior Genetics of the Horse (Equus caballus) - Genetics and the Behavior of Domestic Animals - page 258

seemed motivated by fear, whereas Jenny's vigilance was more like a curi-
ous attention to her surroundings. She didn't always need the company of
other horses and was independent. Unlike Murphy's, carefree independence,
Jenny had confident independence. As the dominant horse in the herd, she
rarely exercised her authority by force: a slight pinning of her ears was all it
took to make other horses back off. When challenged, she let out a squeal
that caused other horses to scatter. On the trail, she refused to follow another
horse. Always the leader, she'd throw a fit if I tried to make her follow.
Behavior differences in these horses was not subtle, neither were the hair
whorls. When I saw similar hair whorls in other horses, I would ask the owners
if their horses had similar behaviors. Clear patterns of behavior and hair whorls
began to emerge. The patterns were still just trends, but it was around this time
that I began to notice another, more consistent behavior related to hair whorls.
Hair Whorls and Side Preferences
The awareness of side preferences in horses is common throughout the indus-
try. The preferred side is easier to handle for shoeing, and horses have pre-
ferred directions when working in circles, or when ridden. The preference for
one side during shoeing was so common that most horse owners would warn
me about their horse's side preference before I started shoeing. I faced this
problem every day. Before long, I noticed the hair whorl side (left or right)
was often the difficult-to-shoe side. A left-side hair whorl predicted left-side
resistance to handling for shoeing. A right-side whorl predicted right-side
resistance, and double whorls predicted resistance on both sides. Hair whorl
and side preference was more obvious than hair whorl height and reactivity.
Side preference for shoeing was even obvious in horses with low whorls and a
calm temperament. By questioning owners, I found the pattern common in all
side preferences, but most common in horses behaving nervously. For exam-
ple, I found that horses with a left-side hair whorl preferred the right side of a
two-horse trailer, and horses with left-side hair whorls approached novel
objects with a left-side bias, keeping the left eye on the object. All these beha-
viors were reversed in horses with right-side whorls, and always more obvious
in nervous horses. Interestingly, horses with two side-by-side whorls showed
less side preference in general. However, in horses with double whorls,
I noticed that one whorl is usually higher than the other. The higher whorl typ-
ically shows the preferred side bias. These observations made my job easier,
and much safer. For example, when I approached a fearful horse with a left-
side whorl for shoeing, I learned to start the job on the horse's right side. This
gave horses an opportunity to get comfortable with me before I handled the
more difficult hair-whorl side. I also found my observations useful when intro-
ducing young horses to the novelty of a saddle, mounting for the first time,
and teaching them to rein to the right or left. Strong side preference seemed to
be always motivated by fear. Horses showing strong side preferences often