Fat is sought out by all omnivores and carnivores.
The idea that there were lots of long bones filled with fat, just lying around to be scavenged, is silly.
The idea that eating rabbits and other small game is not enough to sustain life is silly too.
When carnivores catch a rabbit, they eat all of it. They don't simply strip out the meat, like fastidious 20th century explorers might.
The Canadian Indians survived mostly on rabbits for long periods.
They skinned them and ate the rest of the rabbit. The entire rabbit went into the pot, when they had pots.
The skin was used to make woven rabbit blankets.
The rabbit thing is real... That is why you do have to eat it all including the organs. It is the same with quite a few species of very lean wild game. We just cannot survive without calories from fat or replacements for it.
https://www.raising-rabbits.com/rabbit-starvation.html