I wonder if there'll ever be a time where if we aren't comfortable with doing something to human embryos (or other stages) in experiments, we also won't be comfortable doing it to the animals closest to us on the intelligence and awareness totem pole, and eventually perhaps any sentient animals at all (so nearly all of them besides jellyfish, sponges, anemomes, and some other ocean dwellers). This day feels inevitable to me, but I don't know whether it's 20 years or 200 years away.
Part of that was learning how to track and hunt.
The first time he killed a deer, he was required to sneak up on the deer and kill it with a knife. That way he would know the gravity of what he was doing.
He wrote that he cried for a good while afterwards.
I think that is a perspective more people should take with eating meat. To know you are taking the life of a living, breathing thing to sustain your own life.
I think it used to be a much more common view, but it's hard to view a chicken nugget or a hamburger as an animal that lost its life to continue yours.