The Duke of Cambridge has said the world has just five to ten years to save the rhino - and warned it will be "devastating for humanity" if the species becomes extinct.
William, who like his father the Prince of Wales is a passionate campaigner for animal conservation, demanded "dramatic change" in how the species is protected.
Speaking to ITV News, he condemned illegal poaching, which is decimating rhino and elephant numbers in Africa, and he agreed it is "make or break" time to save the rhino.
William said: "In the next five to ten years if there's not a massive change, a dramatic change, in the way we appreciate and protect these iconic species in Africa, there won't be these incredible animals there, which not only is obviously sad for future generations but I think it would be incredibly devastating for humanity itself when we have sat back and we have lost something we have been responsible for."
Underlining the gravity of his warning, William added: "If we haven't achieved something in the next five to ten years then it will be almost impossible to do anything after that.
"Because the numbers will be so depleted the damage will be done so badly and clearly the demand won't have been halted."