The Buddha taught us not to kill sentient beings, but plants are OK (but not for monastics). Does the Buddha ever define precisely which life forms are to be regarded as "sentient". It seems that generally mammals are the most common examples of what not to kill. What about insects (are they really "sentient")? bacteria? Fungi are neither plant nor animal, and some claim fungi display forms of intelligence (
). On the other hand, jellyfish do not have a brain, does this make them non-sentient?
Of course, even if something is defined as non-sentient, does not mean that we would be skillful in killing the entity for selfish or heedless motives. I am just curious how people in this community define sentience and what creatures they see as having sentience.
I would like to keep this discussion within the Theravada tradition, not referencing any Mahayana, Hindu, Tao, etc. definitions unless they are used to clarify the Theravada view.
Sotthī hontu nirantaraṃ - May you forever be well.