The Biology of the Na'vi

The Na'vi, Avatar's humanoids, were built for looks, not so much for their local environment. For example, they have breasts, big eyes and sternocleidomastoids because human moviewatchers like these features, even though the Na'vi are described as being non-mammalian in other respects.

If you look closely, you'll see that the Na'vi have a little muscle running down their necks. We've got them, too—it's called the sternocleidomastoid muscle—and it's a uniquely mammalian feature. Ours make a very distinctive V-shape, and when creature designers want an alien to seem attractive and familiar to its human viewers, they often slap one on. "Even C3PO has it, in the form of little pistons on his neck. Watch Star Trek: The good guys always have them, and the bad guys don't. It's a classic alien designer trick."

Actually, I wonder if they aren't actually plants, a la the Delvians of Farscape, another bunch of blue skinned, sexy aliens.

More: Mark Morford on the kinky hotness of the Na'vi.