Learn Buddhism, don't dwell too much on this kind of thing. What tigers eat meat, people don't eat vegetables, people drink water and have bacteria, and monks can't get out when they go out and step on ants ... Is this your mentality of learning Buddhism? If we compare the karma caused by tigers eating meat, I am afraid it is far less terrible than the karma caused by these crooked ways in our minds.
I didn't put forward this statement. A case was solved a long time ago. It is said that two Zen masters, passing by the river, saw many small crabs and so on being crushed to death by the docked ferry. One Zen master asked another, Look, is this the fault of the boatman or the ferryman? The other glared: Your fault. Why is it your fault? Because the boatman had to get to the other side of the river, he took the boat right; The ferryman must make a living by sailing, and he is not wrong. Only by persisting in this, we have to twist out some fallacies of right and wrong (or use Buddhist vocabulary: persistence, separation; It is the difference between us and Buddha and Bodhisattva that is really wrong.