This probably has never crossed your mind but evolution plays serious tricks all the time. It has somehow managed to survice ‘this vast variety’ of flora and founa up till now. And there is some evidence to suggest that there were animals that specialized in eating humans.
An animal did evolve as a specialist predator on humans, as remains in caves in Africa have shown. Its name is Dinofelis, and its signature is a pair of puncture holes left in the skull. It has survived in folklore and even in our most basic instincts: every child knows that there is a monster under the bed, and the only way to stay safe is to keep very, very quiet.
When mountain lions and other big cats attack a human, the victim often survives because they cannot bite through the skull. Such injuries are likely to be fatal, but modern cats do not have the best dentition to inflict them; Dinofelis had short, dagger-like teeth that will go through your skull with one good bite.
They were widespread in Europe, Asia, Africa and North America at least 5 million to about 1.2 million years ago. In size they were between a modern leopard and a lion, most being about the size of a jaguar (70 cm tall and up to 120 kg), medium-sized but powerful cats that possessed two prominent sabre teeth. The front limbs were particularly robust compared to the modern cats (even the jaguar). Dinofelis hunted animals including, mammoth calves, young and old mastodons, Homo habilis (an ancestor of modern humans) and other animals.
In ‘Songlines’, Bruce Chatwin suggests that Dinofelis was a major motivation for early humans to invent spears and other weapons, and that our ultimate victory over the Dinofelis and driving it into extinction was a driving force in our evolution. This is speculative, but our apparently universal fear of silent, night-roaming monsters may be an ancestral memory of the man-eater faced by our cave-dwelling ancestors.
The Dinofelis was first identified as a “specialist primate killer” by Prof C K Brain in his 1981 book “The Hunters or the Hunted? An Introduction to African Cave Taphonomy” based on finds in African caves
Sources: quora.com, wikipedia.org, deskridge (cover image)