[ngvrnd]

There is no "why" -- it happened and was not selected against; it may have been adaptive and that is a kind of why, I guess. I think it would be better to be clear about this in science communication.

[Hackbraten]

The article itself states that this may be the case, or that it might have had some evolutionary advantage that we're just not aware of.

[BoiledCabbage]

> There is no "why"

Of course there is a why. It happend and not only was it not selected against, presence of a tail was selected against. Meaning it was, or came along with a beneficial adaptation. That benefit is why it took over our gene pool and why we don't have tails now.

[Smaug123]

The article itself is very clear about the sense of the word "why" intended here.

[JBiserkov]

Yes:

> But while the new study explains the “how” of tail loss in humans and great apes, the “why” of it is still an open question.

Title is still clickbait.

[o-o-]

There has to be more to it.

If it’s not selected against, it wouldn’t spread at the cost of the tail gene.

Somehow, somewhere along the genome line, non-tailers overtook tailers.