It’s everywhere. Why not just eat it instead of searching for veggies and meat which are more difficult to have?
Smarts required more calories.
Grass is mostly cellulose and lignin. Those molecules are difficult to break down.
Animals that can digest the cellulose either need a really long digestive track or to do something really gross to keep the stuff in their digestive track longer.
Any chemistry we could perform to make it more viable? E.g. cook it with alcohol?
Folks have looked at it with acid or enzymes to try and produce fuel ethanol from the sugar forming the cellulose. Humans use the chemistry of grazing animals.
Yeah the grass to milk, meat and hide pipeline is a great one
It’s more efficient to let others eat the grass, and then eat them
It’s all down to the way the brain works. Our brains use up something like 20% of our calories when standing still doing nothing.
Grass does not supply the amount of calories and micronutrients needed to keep the human brain running, simply because it is low on both of those things.
Grass eaters have multiple stomachs, slow digestion and graze pretty much the whole time they’re awake, and because their brains use a lot less energy than human brains, the balance works out.
The thing is that cows can’t digest grass either. They have an extra stomach along their oesophagus which is basically just a pouch where the grass goes in first. There are a lot of bacteria and they can digest grass. Then these bacteria grow because they eat the grass.
Then the cow swallows these bacteria and digests those. That’s where a cow gets their calories from.
Humans can’t digest anything without bacteria either.
they can
when you eat fruit, the sugar can enter your bloodstream directly through the mucosa in your mouth, you don’t even need to swallow it. although the main part of the absorption happens in the colon still.
Albeit true, not to the extent of cows.
Cows only have 1 stomach. That is devided in 4 compartments.
Return to cow
Take the tier zoo aproach. Would you rather use evelution points on grass or evolution points on being big brain.
Grass.
Some of us did that and they are horses now.
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Vegetables have pretty limited availability for protein, as an animal you have sit there eating grass all day. Our ways allow us plenty of time to be smart & stuff
Essentially as others said, because you need to invest heavily in your gut and metabolism to get enough energy out of grass alone. You don’t evolve into what you want, you evolve into what you can while you are pressured to do so. There is currently no pressure to rely solely on grass, that pressure hasn’t been on us for millions of years. Our foods may be trickier to find but on average they yield more energy compared to grass.
But don’t get me wrong. It’s a valid strategy. Our ancestors did have the window of opportunity at some point, and they took it… We were something more like rats back then, the grass eaters niche had room. Grass was everywhere. And our cousins back then adapted and spent practically the whole day foraging for grass in order to get by. But you know what also was everywhere? Trees. And our ratlike ancestors that were more inclined to climb, jump, and spot predators from above found it easier to stick to the omnivore diet.
Adapting to trees lets you move into places with less grass… Like jungles and swamps. And while you are there for a couple million years you will have other problems to solve, problems that require wits, sharp vision, and social skills. You don’t have time to forage 18hrs every day and grass isn’t as abundant here anyway.
If you don’t rely solely on grass you will probably fare better during winter. Especially during those ice ages. By the time you have grass as an option again you are pretty much an ape and pivoting back to it makes no sense.
Because yo mama so fat she’d eat it all
I’d rather evolve the ability to photosynthesize, now that we have indoor lighting. It’d save a whole bunch of time and grocery bills.
That random mutation didn’t happen, basically.
Evolution is a purely subtractive process. It doesn’t design things in, it just removes poorly-designed creatures (and all hypothetical offspring) until only things equipped to survive are left. And obviously, there are things to eat that aren’t grass.
Edit: Herbivores can be smart, even the grazers. Look at elephants.
I can’t believe how many other replies heap that fallacy on top of teleological evolution. Apes are mostly herbivorous anyway, WTF.
Evolution is not subtractive. Bacteria didn’t evolve from humans
In the sense humans are “better” or “greater” or something? Well, consider the global biomass of bacteria compared to humans - they seem to be doing okay. Or that there’s more bacterial cells in you than human cells. Single-celled yeast evolved from mushrooms, barnacles evolved from something like shrimp or crabs, and there are eukaryotes that lost eukaryotic features like mitochondria because they didn’t need them to survive.
Buuut that’s besides the point. I’m not sure how to make it more clear, but I meant subtractive as in selection is just about who dies. Random mutation is what adds features and new species.
Why haven’t cows evolved sentience?
Grazing lifestyle doesn’t favor big expensive brains.
Sentience is the ability to perceive your surroundings using your senses. What cows (probably) haven’t achieved is sapience, roughly the ability to think about more than your immediate sensual impressions, in the abstract. Modern humans have decided they are extra sapient, hence “homo sapiens sapiens” whereas Neanderthals are “homo sapiens neanderthalensis”.
I think that grass don’t have enough energy to sustain our brain and its development.
If you look at all the other animals in the world that do eat grass, we did. But the “we” that eat grass, look like those animals, with those traits.
The “we” that became smart became so due to what we evolved to eat and do.
