The genetics of hair whorls

New research provides evidence that a horse's "cowlicks" may indicate that he has certain behavioral traits.

Research from Brazil may provide the first step in linking hair whorls to particular personality traits in horses.

Areas where a horse’s coat grows in a spiral-like formation, hair whorls can occur anywhere on a horse’s body, but those on the head and neck tend to draw the most interest.

Anecdotally, hair whorls have been linked to spookiness, playfulness and other behavioral tendencies in horses. It has already been confirmed that horses with whorls above the eye line are more difficult to handle.

People have long suspected that a horse’s hair whorls are clues to his personality.

For their study, researchers at the Federal University of Bahia and the São Paulo State University analyzed genetic polymorphisms from 342 Quarter Horses, focusing on about 53,000 variations in DNA sequences called single nucleotide polymorphisms (SNPs).

They sought to identify connections between SNPs with some specific whorl traits, including frequency and location. 

The resulting data linked hair whorls to specific regions on the genome, including some where genes governing hair follicle growth were located. “Curiously,” note the researchers, “some of these genes also have known neurological and behavioral functions.”

The researchers say this is the first indication that the long-standing horsemen’s observations and previous scientific behavioral findings about hair whorls may be validated by genetics.

Reference: “Genomic regions associated with the position and number of hair whorls in horses,” Animals, October 2021.