What’s in a rhino horn?

Many of you already know that last year, our southern white rhinoceros Mumbles got a new companion! Kiazi arrived from San Diego Zoo Wildlife Alliance last October, and after months of gradual introductions, the two are comfortably settled in their habitat in the African Savanna area of the Zoo.

Visitors to the rhino habitat often have questions about Kiazi’s horn, which currently has a blunt end. Many wonder if she injured her horn, or if she was born with a blunt horn. This gives us an excellent opportunity to share a fascinating, lesser-known fact about rhinos: their horns grow back!

Before Kiazi’s journey to Zoo Atlanta, Kiazi had a very long, pointed horn.  Her horn was trimmed prior to transport to reduce the chances of accidentally hurting herself or a member of her care team during transit. This was merely as a precaution, as Kiazi had ample opportunities to experience going into her travel crate, entering it voluntarily, and being comfortable there before embarking on the trip. Her horn will gradually grow back in its entirety over the next couple years.  In fact, she has been hard at work since she got here, honing her horn on rocks and walls of her habitat to regain the point.  She has made very good progress, and soon, we won’t be able to tell them apart simply by their different horns.    

Unlike most animal horns, which are comprised of a bony core coated by a relatively thin layer of keratin, rhino horns are solely made of keratin, a naturally produced protein that strengthens hair, skin, and nails in humans. Both males and females have horns in all five rhinoceros species. Recent studies from Ohio University have demonstrated that the centers of the horns have dense mineral deposits of calcium and melanin. The calcium has a strengthening function, while the melanin protects the core of the horn from UV exposure.

Unfortunately rhino horns continue to hold value on the black market. The resulting poaching, combined with habitat loss, has led to three subspecies of rhino (eastern black, Javan, and Sumatran) being classified as critically endangered, while western black rhinos and northern white rhinos have gone extinct in the wild. Thanks to extensive conservation and protection measures, southern white rhinos like Mumbles and Kiazi are now classified as near-threatened, although ongoing efforts are necessary to ensure their continued survival.

Don’t forget to stop by the African Savanna and check out Kiazi’s re-growing horn in person!

Sources:

Rhino Horn Use: Fact vs. Fiction. PBS. (2010, August 10). Retrieved August 8, 2022, from https://www.pbs.org/wnet/nature/rhinoceros-rhino-horn-use-fact-vs-fiction/1178/

White Rhino. World Wildlife Fund. (n.d.). Retrieved August 8, 2022, from https://www.worldwildlife.org/species/white-rhino