A rhinoceros's horn is distinctive, and the name "rhinoceros" actually comes from the Greek words for "nose" and "horn." But despite its size and strength, the horn is composed primarily of a protein called keratin--the same substance that makes up human hair and nails.
Unlike other horned animals, which have a bony core encased in keratin, rhinos have only mineral deposits of calcium and melanin at the core of their horns, more akin to hooves and beaks, according to researchers at Ohio University. The same study confirmed that horns are sharpened by honing, similarly to a pencil. Variations in rhino horn keratin composition, due to diet and geographic location, can be used similarly to fingerprinting to identify the animals, allowing ecological researchers like Raj Amin of the Zoological Society of London to determine which population a rhino belonged to. This information is helpful to law enforcement officials in cracking down on illegal poaching.
The rhino horn was once believed to contain medicinal properties, ranging from stopping nosebleeds and headaches to curing diphtheria and food poisoning and enhancing libido. However, studies by Swiss pharmaceutical firm Hoffmann-La Roche and the Zoological Society of London dispelled claims that rhino keratin bears any effect on the human body, and using the horns for medicinal purposes has been illegal since 1993.
Poaching and Trade
Although rhinos are a protected endangered species, the value of their horns is the main reason they are still being illegally hunted. As of 2010, rhino horns sell for $21,000 to $54,000 per 2 pounds on the black market.