(CNN) After 40 million years, the Sun may be setting for one of the world's largest land animals. Three of the five surviving rhino species are critically endangered, poaching rates are off the charts, and the northern white rhino is down to a single representative.

A single horn can fetch $100,000 in Asian countries such as China and Vietnam, where there is intense demand from buyers who mistakenly believe it can cure health problems from hangovers to cancer, or use it as a lifestyle drug. The global market is worth around $500 million, and growing rapidly.

The figures are daunting for conservationists, but a California biotech startup believes it has a solution. Pembient is producing synthetic rhino horns to offer consumers an ethical alternative. After a lengthy development period, the finished product will be on sale within months.

The process involves fabricating protein that the team claim is identical to the keratin found in rhino horns. That protein is produced as a powder, which is then shaped and manufactured with advanced 3D printing techniques until it is indistinguishable from the real thing.

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The tools and techniques required have finally matured enough to make this possible, says CEO Matthew Markus.

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