This is an unpopular opinion, and should be wielded very carefully, but I think something often lost in these conversations is that the existence of a human behavior in an animal is not sufficient evidence that it's backed by the full weight of the human-like mental states. It may well be, but additional evidence must be presented.<p>As humans, we're strongly prone to anthropomorphize–I'm capable of ascribing human feelings even to inanimate objects–and so are prone to doing the above without rigor.<p>An extreme example: if you drop acid into the water in which a paramecium lives, it will fire up its cilia and frantically try to retreat. It's a single cell, there is no suffering or mental states, but it sure looks like it.<p>An ant could have a sad looking death, but it surely cannot reach the depths of human sorrow, and the related suffering, that a similar event could elicit. It can't mourn the time it won't spend with its children, or the ways its life could have gone.<p>I'm not proposing that everything between us and the paramecium cannot suffer, but that arguments in these areas must go beyond X has behavior Y, so X must have full mental state associated with Y.