Samplings: February 2020

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Rhino horns are comprised of hair bound together by glandular secretions.

Fritz Vollrath

Rhinoceroses (Rhinocerotidae) are among the most imperiled mammals on Earth, due primarily to poaching to meet consumer demand for their horns, which are used in alternative medicine or as status symbols. One proposed solution to reduce poaching is to “game the marketplace,” so to speak, with fake rhino horn. To that end, scientists recently synthesized a product made from horsehair and silk proteins that is chemically and structurally nearly indistinguishable from real rhino horn.

A rhino’s horn is actually a tuft of hair growing out of its nose, held together in a matrix of sticky glandular secretions. University of Oxford’s Fritz Vollrath, whose main expertise is the biochemical properties of spider silk, collaborated with Ruixin Mi and Z.Z. Shao of Fudan University, Shanghai, China, to produce a rhino horn mimic out of commercially available horsehair. To make the faux horn, they first washed and exfoliated the horsehair with a solution of lithium bromide to remove the hair’s oil and external scales. They bundled the treated hair and placed it in a mold with a silk-cellulose mixture. After the bundle was cured by drying in a vacuum oven for several weeks, it was cut and polished to look like rhino horn.

Light and scanning-electron microscopy confirmed that the synthetic horn’s structure was similar to that of real rhino horn. Additional analyses verified that its thermal, mechanical, and chemical properties were similar as well. Researchers believe their synthetic horn can be cheaply produced and is sufficiently difficult to distinguish from real horn and thus will sell.

Vollrath acknowledged that there is active debate about whether attempts to flood the market with fake horn will be beneficial or detrimental to rhino conservation. He stated that “since the market is a supply and demand issue,” he hoped that accepted fakes “can disrupt the market.” The next step in rhinoceros conservation could be to convince others to mass-produce this faux rhino horn based on this newly developed recipe. (Scientific Reports)