A ‘cowlick’ in animals.
Fur that grows in a twirl. The fur grows in a different direction from the normal direction. Depending on where these ‘cowlicks’ are, the animal is said to be prone to horn others, will have a short life, the owner of it will have good harvests, etc.
That water buffalo has five cowlicks.
That water buffalo has a cowlick that shows he will butt.