Fake rhino horns made from horse hair could save endangered African icons

A rhino drawn to life, showing to the right both length and cross sections of slivers of its horn. Credit: Jonathan Kingdon

Fake rhino horns made from the tail hair of horses could be used to flood the black market, helping to save these critically endangered pachyderms from poachers.

Demand for rhino horn is driving poaching, which is having a catastrophic effect on rhino numbers, with few individuals left among the few surviving species.

Scientists have been working toward new strategies in a bid to save the rhino.

The animals’ survival is critically challenged by the horn trade, and a range of horn substitutes are being developed and apparently marketed with the ultimate goal of undermining the market in this much sought-after — and generally banned — commodity

Researchers Ruixin Mi, Zheng-Zhong Shao and Fritz Vollrath have added their impetus, reporting in the journal Scientific Reports on their successful efforts to create fake rhino horns.

They hope their method will provide a blueprint to create credible fakes that could eventually flood a market that has decimated the wild rhino population.

In Chinese medicine, rhino horn is believed to have many benefits, including working as an aphrodisiac. In reality, sellers are often cutting the horn with ground-up Viagra.

Whatever the exact hidden blend may be, the undimmed demand for rhino horn continues to drive poaching.

The three scientists developed their substitute, which they hope will provide a way to confuse and thus hopefully diminish the demand for real rhino horns by showing a way to a vastly cheaper copy that can be used to infiltrate the market.

Images of cross-sections of a real rhino horn (A,C) and an artificial horn (B,D). Images of cross-sections of a real rhino horn (A,C) and an artificial horn (B,D). Ruixin Mi et al. https://doi.org/10.1038/s41598-019-52527-5

The horn of the rhinoceros is not a horn in the traditional sense like the horn of a cow or the nail of a hoof, though it does share some material properties.

The rhino’s horn is actually a tuft of hair that grows, tightly packed and glued together by exudates from sebaceous glands, on the nose of the animal.

For their research, the trio bundled together tail hairs of the rhino’s near relative, the horse, and glued them together with a specially tailored matrix of regenerated silk to mimic the collagenous component of the real horn.

This approach allowed them to fabricate sample structures that were confusingly similar to real rhino horn in look, feel and properties. Analytical studies demonstrated similarities in composition and properties between natural and fake horns.

“It appears from our investigation that it is rather easy as well as cheap to make a bio-inspired hornlike material that mimics the rhino’s extravagantly expensive tuft of nose hair,” said Vollrath, from the University of Oxford’s Department of Zoology.

“We leave it to others to develop this technology further with the aim to confuse the trade, depress prices and thus support rhino conservation.”

The authors believe it is important that plausible copies should be simple to produce while being very similar in both structure and chemical composition. And tail hairs from horses, glued together with a silk-based filler, seem to fulfil this condition.

Importantly, this bio-composite is easily moulded into a rhino horn copy with a microstructure that, when cut and polished, is remarkably similar to that of the real horn.

Mi, from the Department of Macromolecular Science at Fudan University in China, said: “Our study demonstrates that materials science can contribute to fundamental issues in biology and conservation.

“The fundamental structure of the rhino horn is a highly evolved and tough fibre reinforced bio-composite and we hope that our attempts to copy it will not only undermine the trade in rhino horn but might also find uses as a novel bio-inspired material.”

For comparison work, the trio used material from a documented horn of a Black Rhino collected in 1935 in what was then Southern Rhodesia. This was compared with younger horn material coming from a zoo-bred white Rhino which that had died more recently.

They were found to be very similar in both fine-grained dimensions and structure but different in colour, with the latter requiring grey rather than black horse tail hairs for impostor horns.

In their paper, the trio wrote: “Our artificial silk and horsetail rhino horn mimic did rather well in our comparative analyses.

“Optical and scanning electron microscopy showed similar outer appearance and inner structure between real and artificial materials. Thermal analysis of both horns showed comparable thermal stability.”

Fourier Transform Infrared Spectroscopy showed very similar results between the real deal and the fake, which they said would make it rather difficult (and with a little tweaking perhaps even impossible) to distinguish the artificial horn from its rhino model using a handheld spectrometer.

Shao is with the Department of Macromolecular Science and the Lab of Advanced Material at Fudan University.

Mi, R., Shao, Z.Z. & Vollrath, F. Creating artificial Rhino Horns from Horse Hair. Sci Rep 9, 16233 (2019) doi:10.1038/s41598-019-52527-5 

The study, published under a Creative Commons License, can be read here

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