If that is your view , then it follows in your view that killing a child of less than 4 isn ' t serious harm or killing an a person who will not achieve cognitive development beyond that level . I am thankful that is not a common view . When a lion kills an antelope , nothing immoral has happened just like how we would say in those tragic incidents where a toddler finds a gun and kills someone that toddler has not done something immoral . That is because though the toddler and the lion are sentient and have interests worth protecting in my view ! They aren ' t moral agents . They aren ' t capable of participation in a conversation like this or of understanding morality so they cannot be held to the same standard . In the lion ' s case , he doesn ' t have an alternative and killing for him is survival which if he were a moral agent would make his killing permissable in a way that killing isn ' t for humans in modern society . That leaves aside the question about whether we should act to protect the gazelle who has feelings and interests too . Theoretically , if we knew how to act to reduce overall suffering and increase happiness in wild animals I think we should . However , in practice that ' s not simple taking out predators changes ecosystems in ways which may not reduce suffering overall . Inaction or action to restore ecosystems to their sometimes harsh status quo may be the path of least harm according to what we know today , but that does not mean that animal interests don ' t matter . And it doesn ' t absolve us from doing the right thing when the right thing is obvious and practical .