mistfree: "OK I give up! How the He!! do they know it was a hyena the ate him?"
Obviously, they don't know, are merely suggesting a likely possibility.
Why likely?
Well, because hyenas are the world's apex scavengers, and it's considered unlikely that Neanderthals would be brought down by a predator.
The Denisova cave findings included 27 species of large & medium sized animals, including as this article mentions mammoths, woolly rhino, wolf, and reindeer, but also cave lions and cave hyenas.
So, perhaps there were more hyena bones than other predators, or hyenas more closely associated in stratigraphy, or even something about hyena digestion which makes bones more likely to pass through?
But I'd suppose it just as likely that Denisovans were the first Democrat politicians, about whom it's well known that if you are not at their negotiating table, then you will certainly be on their menu.
Hyenas? Well, political jackals for sure.
Cave hyena reconstruction, cave lion drawing, actual lion & jackal:
