Why do lions lick their prey a lot before they start eating it?
Like all felines (including the domestic cat), the lion’s tongue is covered in small, hook-shaped growths called papillae, which point towards the back of the mouth, and are used as a brush to separate the flesh from fur and bone, particularly when the cat is feeding on a humongous kill (wildebeests, buffaloes, zebras…) – in the case of smaller prey items (rabbits, rodents, birds…), the carcass is devoured whole, with only a few or no bone splinters left.
Moreover, these papillae have the feeling of a hairbrush, resulting in the tongue becoming a rough surface – they’re sort of like hairs because they’re made of keratin, which is the same protein a human’s hairs and fingernails are composed of.
In the process, the feeding lion consumes the skin completely, and ensures itself that it never swallows (even accidentally!) small, pointy bones that could rip the cat’s throat, and that the meat is tenderized, which renders it efficiently digested.
Now, a lot of lions have seen to be licking prey they’ve just hunted, before killing and eating them. This mostly happens when the prey (usually an ungulate youngster) is brought alive by the lionesses to their cubs, so that the latter can hone their hunting skills – in the process, these cubs are too young to understand the art of hunting and the throttling bite that is essential to make a kill, so they instead resort to playing with the animal by chasing it around; and when they subdue it, they don’t immediately kill it, but rather lick it, possibly as a means to display youth innocence.
This behavior mainly occurs with lion cubs (the youngsters, naturally), but it’s seen in adult lions too – in this case, it’s not always clear why. In my opinion, it could be psychological, in a way that the hunting lion either resorts to licking the animal in order to calm it – either it’s something done prior to giving the prey a quick death, or because something snapped inside the lion, a friendly, empathetic thought that made it reconsider its ferocious behavior, particularly since the hunted animal frantically panics from being attacked by a predator, emitting gut-wrenching cries for help –, or it’s just playing with its food (like house cats do), perhaps to torment the prey or simply tire it out so as to not risk injury. But I’m just speculating.
In the end, no one knows exactly why lions (the adults, to be precise) resort to licking their prey a lot while it’s still alive, prior to eating it.