Earlier quoted context omitted.
A number of replies to this comment point out that modern animals also eat bone marrow. However, that may have not been the case a couple million years ago. In “Guns, Germs, and Steel”, Diamond points out that animals in Africa are particularly vicious and dangerous due to their coevolution with humans. Animals outside of Africa rapidly went extinct as evolved humans spread to the rest of the world, since they didn’t…
The chances of a highly nutritious, energy dense food being just left to go to waste by nature are practically zero. There are many, many examples of animals becoming highly evolved/specialised to exploit such food sources in habitats that don't feature humans (e.g. the oceans). The GP comment was an egregious example of a "Just-so story".
Well, humans are nature so..