But one thing that seems pretty clear when we look at human religion is that it's highly tied in with human culture. So if, as seems to be the case, culture's governing a lot of what whales do, it's perhaps not an unreasonable hypothesis to think that it's got elements of...what I guess you'd call the supernatural.

I don't think in biology it's very controversial at all. Whether certain behavior is culture or is not culture is argued. I think virtually all biologists would agree that some animal behavior is culture. Bird song is a good example.

But one thing that seems pretty clear when we look at human religion is that it's highly tied in with human culture. So if, as seems to be the case, culture's governing a lot of what whales do, it's perhaps not an unreasonable hypothesis to think that it's got elements of...what I guess you'd call the supernatural.

When I'm out in the ocean and I watch a seabird, I think, "Oh, I probably I know what that seabird is doing" - and I don't study seabirds. And the same for the turtles and on and on. But with the whales, a lot of the time, I have no idea what they're doing, and they're the ones I study.

Culture is not usually one of the criterion for personhood, but it has been argued that culture is sort of a medium for a lot of these criteria, such as empathy, and so on.

What I mean by it, and roughly what most biologists who talk about culture mean by it, is either behavior itself, or information that leads to behavior. Information that is picked up through social learning - so, from being with, watching, being taught by others. It's a way that individuals behave or get information about how they will behave that comes directly from the behavior of others.

Humans are particularly interesting; our culture is incredible, there's no doubt about that. In many respects, no other species matches ours. But in quite a few respects, they do, and that can help us, perhaps, to better understand our own culture. We look at the ways humans are similar to other animals, and at the ways they differ, rather than just saying, "We have culture and you don't."