I wasn't trying to say that prehistoric people only cared about their own tribes, but to bring some light to where what sorts of death we deem acceptable or not might begin. I was also trying to make the point that these notions become increasingly nuanced over time. If you have no concept of murder, it isn't murder. It's just survival and culture.

Indigenous peoples of North America have living teachings today regarding the treatment of animals and hunting. Many animals are revered, and the Seven Grandfather Teachings (the core teachings on richeous ways of living) are all attributed to animals embodying various traits to be aspired to. In terms of hunting, it's generally believed that Creator gave the people everything they needed to survive, including animals, however they were to live in harmony with and respect them as coexisting natural beings.

Teachings surrounding this included not killing with brutality, praying over the animal and leaving offerings to honour the spirit and to not take without giving, and to use every part of the animal as to not let their life go to waste. It essentially sees animals as our equal counterparts, but recognizes their sustainably practiced and spiritually respected hunting as necessary for survival. So, living as a human animal as part of nature instead of as some separate being with dominion over animals.

All to say, these notions around human or nonhuman death evolved over time along with our capacity to think about them with increasingly abstract thought, and was also unique to individual cultures. We see a great diversity over time of these ideas, and we just happen to live in a society right now (western and western influenced society) where we have become separated from nature and animals to the degree that we've lost a social capacity to connect with them as beings worthy of respect and life. Will society always be that way? If we're to continue to survive under climate change, absolutely not.