What about situations where humans need to eat
meat to survive?
This situation exists for a few cultures which have virtually no contact with the industrialized world, and which live in geographic areas where the native vegetation does not permit a vegetarian diet.
I believe that the reason that it is not wrong for animals such as lions to eat meat is because two conditions are both simultaneously met. These conditions are that lions genuinely need to eat meat to survive, and that the ecological balance of the area depends on lions hunting their prey.
If both of these conditions are met for humans, as they are in a few existing non-industrialized cultures, then I believe that these humans are as ethically justified in hunting animals as are lions. So I do believe that eating meat is ethically permissible in certain hypothetical situations.
I also believe that cannibalism is ethically permissible in certain hypothetical situations. For example, suppose a group of people are stranded on a desert island, and they will all die of starvation prior to being rescued unless they cannibalize each other. In this hypothetical scenario, I believe that cannibalism is ethically permissible.
However, the fact that eating meat may be ethically permissible in certain hypothetical scenarios should not be an excuse for us to engage in it when the conditions of these scenarios clearly do not apply to us.
Although the following is probably obvious, I feel I should emphasize that my answer to this question is my own personal opinion (as are my answers to most other questions) and does not necessarily represent the views of other animal rights supporters.
Follow up questions:
Isn't hunting by humans necessary to prevent deer overpopulation?
How common is cannibalism in the animal kingdom?
Isn't it unfair and insulting to compare the murder of a human being with the slaughter of animals?