![Photo of life-size Black Rhinoceros model.](https://www.frostscience.org/wp-content/uploads/2021/06/tough_skin_featured.png)
Unlike most mammal horns made of bone covered by a thin layer of protein-rich keratin, sturdy rhino horns are made entirely of keratin, anchored to the animal’s thick epidermis.
Unlike most mammal horns made of bone covered by a thin layer of protein-rich keratin, sturdy rhino horns are made entirely of keratin, anchored to the animal’s thick epidermis.