Meat Eaters
In Gen. 8 we read that when Noah sent out a raven, the bird didn’t return, but the dove did.
Was it because the raven was a scavenger, and the dove was not?
I don’t think so, because there were no scavengers up to that time.
The text also does not say that the raven found anything to eat.
It only says the raven went to and fro, and that the dove found no resting place.
Rest
I would suspect that both birds did not fly out hungry, as they had food in the ark.
So it wasn’t about food, it was about a resting place.
A raven doesn’t need much to rest, a piece of driftwood or something similar, would already suffice.
But a dove has to build a nest first, and he couldn’t accomplice that task yet.
And that also explains the piece of leaf it had in it’s beak.
On his second flight, the dove was able to start his nest, but it was not yet finished.
So, when he got tired he flew back to the ark, with another piece of “work” in it’s beak.
The following week he finished his nest and was able to rest on it without having to return to the ark.
Vegetarians
At the creation, God said that humans could eat herbs and fruit, and to ALL animals God gave the green crop.
So mankind, and all animals, were herbivores and nowhere do we read that God changes this.
Not until Noah came out of the ark and God gave Him a new commandment.
(Btw, the only animal that was changed after the fall was the serpent, He lost his legs, and he would eat dust.)
And I don’t think that the fact that there were clean and unclean animals before the flood, alters this.
That only means that God had already made it known which animals could be sacrificed to Him.
See, for example, Abel’s offering of the firstfruits of his flock.
(the separation between clean and unclean is also different from herbivores and carnivores).
Meateaters
In Gen. 9:2-6 we read:
And the fear of you and the dread of you shall be upon every beast of the earth, and upon every fowl of the air, upon all that movethupon the earth, and upon all the fishes of the sea; into your hand are they delivered.Every moving thing that liveth shall be meat for you; even as the green herb have I given you all things. But flesh with the life thereof, which is the blood thereof, shall ye not eat.And surely your blood of your lives will I require; at the hand of every beast will I require it, and at the hand of man; at the hand of every man’s brother will I require the life of man. Whoso sheddeth man’s blood, by man shall his blood be shed: for in the image of God made he man.
After Noah came out of the ark, the animals became afraid of humans.
So, before the flood, the animals had no fear of humans (and vice versa).
Also, from now on, humans can eat meat, but subject to rules.
And God also gives rules about how to deal with an animal that kills a human.
Apparently that is only an issue from that moment on.
And now I’m going to speculate a bit:
Before the Fall, meat was both forbidden and unnessecary.
Humans could, and did, live to be very old on a vegetarian diet, because the earth provided plenty nutricious herbs and fruit.
And the animals likewise, lived on plentiful greens.
But the earth was thrown off its axis by the flood and became tilted. This created rain and drought, jungle and polar regions.
The seasons started, and it stands to reason that the “plentiful vegetation” would deminish to a certain extent.
In this new environment, God gave a new “circle of life”. And was it good for people and (some) animals to also eat meat.