What material makes up most of a rhinoceros’s horn?

Most of a rhinoceros’s horn is made of keratin, the tough protein also found in human hair and fingernails.

Unlike antlers, a rhino horn is not a bony structure attached to the skull. It is a compact mass of keratin fibres that grows from the skin. The horn can continue growing throughout the animal’s life and may regrow after partial damage, although its shape can change.

Rhinoceroses use their horns for defence, competition and displays. Depending on the species, a rhino may have one or two horns. African species generally have two, while the greater one-horned rhinoceros has one prominent horn.

The value placed on rhino horn in illegal markets has driven severe poaching. Scientifically, it has no proven medicinal benefit. Removing a horn does not guarantee safety, because poachers may still kill the animal and regrowth is not always complete.