Interesting review of a new book portraying behavior of animals that can fairly be described as moral (via). I think our resistance to seeing animals as in any way “moral” might be rooted in the Kantian legacy of modern moral philosophy. Roughly, for Kant, you’re only acting morally when you’re acting for the sake of the moral law, and in opposition to some natural inclination. By contrast, the Aristotelian tradition says that a moral agent is someone with the dispositions toward and habits of performing virtuous action. By that standard, many non-human animals would count as virtuous.

UPDATE: See John’s post here. I did speak hastily in characterizing Kant; acting morally for Kant doesn’t necessarily require acting in opposition to a natural inclination, but rather for the sake of the moral law (though there does seem to be something especially virtuous about doing what duty demands even when we have a strong inclination not to). John also points out that Aristotle is closer to Kant here than my post makes it sound.