Biology Reference
In-Depth Information
A physical characteristic present at birth that remains unchanged
throughout life, is easy to see, and predicts the biological foundation of
temperament could have enormous implications. Hair whorls could be that
characteristic. The fact that hair whorls are linked to early fetal brain
development and are similar in type and distribution across at least four
mammal species is remarkable. Hair whorls may provide clues to under-
standing pattern formation mechanisms in nervous system development. All
mammal brains are basically similar in both structure and function. Even a
superficial examination of the external anatomy of the brains of vertebrates
reveals that most vertebrates possess the same number of brain divisions.
All vertebrate brains have a brain stem, limbic system, cerebellum, and
cerebral cortex. The main difference between the brains of humans and
other animals is the size and complexity of the cortex. In addition, basic
behaviors are similar in humans and animals, and in more complex human
behaviors such as fine motor skill and language, there may be precursors in
animals. Animals also respond to the environment much as humans do,
reacting emotionally to others and even becoming stressed and anxious in
times of danger. Therefore, it requires no stretch of the imagination to
assume that hair patterns and brain development follow a similar trajectory.
In the past, people read too much into hair whorls in terms of horses' per-
sonalities. The way we like to explain it, hair whorls may simply predict
how easily an animal gets scared. Personality, like temperament is shaped
by a complex interaction between genetic factors and experience. Hair
whorls don't predict that a horse will have certain temperament or person-
ality traits, only that the horse is predisposed to those traits and up-
bringing and experience determine if those traits are expressed. In day-old
foals, the first author is fond of saying, “Hair whorls are like a built-in
instruction manual.”
The recent discovery that the horse brain is lateralized and the two hemi-
spheres are specialized to handle information in different ways, and control
different classes of behavior, has the potential to solve many common pro-
blems. In our observations in cattle and horses, lateralized behaviors are
signs of stress and fear. Repeatedly exposing horses to stimuli they perceive
as threatening or dangerous can have profound effects on health, welfare,
and productivity. Recognizing fear as the primary motivation of lateral
behavior provides an alternative to correcting behaviors once established, but
more importantly, a way to prevent the behaviors before they begin. Hair
whorl side position and laterality has been shown in cattle and dogs, but
further research is needed to find if hair whorl side position is related to
laterality in horses.
Good horse trainers are talented observers of horse behavior and respond
consistently to the horse's subtle cues during training. Learning the differ-
ence between individual horses and how they react differently to different
situations is the key.
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