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Three decades ago, in the 1990s, molecular biology revolutionized the classification of living beings. Until then, the classifications were based exclusively on anatomical characters, which in many cases was misleading. For example, it was believed that the closest relatives of hippos were pigs and wild boars until genetics showed that they are closer to ruminants. But the most surprising thing is that ruminants are not the closest relatives of hippos either; the closest living relatives of hippos are… cetaceans, that is, whales and dolphins. So cetaceans have to be classified within the group of ungulates, with cows, pigs, deer, antelopes, camels…