Why some humans grow horns

Cutaneous horns are compacted keratin masses that grow outward from a person’s skin. Their typically curved shape and hardened texture make them look like the horns of a goat, sheep or cow. [AI Generated Image]

Equids, members of the horse family including horses, donkeys and zebras, share curious features called chestnuts. Found on every horse, they appear as toughened growths on their limbs, and can be clipped back if they grow too large.

Anyone following the charming and rugged farrier Sam Wolfenden on TikTok will have seen his expert chestnut clipping.