A hair whorl is a patch of hair growing in the opposite direction of the rest of the hair. Hair whorls can occur on animals with hairy coats, and are often found on horses and cows. Locations where whorls are found in equines include the stomach, face, stifle and hocks. Hair whorls in horses are also known as crowns, swirls, trichoglyphs, or cowlicks.
Hair whorls are sometimes classified according to the direction of hair growth (e.g. clockwise or counterclockwise), shape, or other physical characteristics.
Anecdotal evidence claims a statistical correlation between the location, number, or type of whorls and behaviour or temperament in horses and other species (but see Correlation does not imply causation). There is some research suggesting that the direction of hair whorls may correlate to a horse's preference for the right or left lead and other directionality.
The theories that hair whorls could describe various physical and personality characteristics in horses have been around for thousands of years.
There are references of hair whorls in the works of the Indian sage Salihotra. Bedouin horsemen used whorls to determine the value of horses for sale. One Arabian horse has been recorded with 40 whorls on his body, although the average horse has around six. Bedouins looked for whorls between the horse's ears as a sign of swiftness, and if there were any on either side of the neck, they were known as the 'finger of the Prophet'.
One legend of whorls is the "Prophet's Thumbprint" a birthmark in the form of an indentation, usually found on the side of a horse’s neck, totally harmless although it comes with a legend.
The Prophet Mohammed was wandering the desert with his herd of horses for many days, and as they approached an oasis he sent them forth to drink. But as the thirsty horses approached the water, he called them back. Only five of his mares stopped and returned to him, and to thank them for their loyalty he blessed them by pressing his thumbprint into their necks.
It’s believed that a horse with such a mark will be outstanding, being a descendant of one of these brood mares that the Prophet Mohammed particularly treasured.