Yeah, that's a bizarre headline. I'm not sure it's wrong, but it's quite strange.

Edit: I'm not sure actually right either. It was not the act of eating that transported the bodies; rather the bodies were brought there so they could be eaten.

"Hyenas dragged 9 Neanderthals to a cave to eat them."

Both are fine, if you remove the comma in your example, but the one used in the article puts the focus on "eating" first. It's also more interesting to read: "By eating them..." (who ate who or what?) ..."hyenas gathered neanderthal skeletons" (oh good, interesting archeology, I'll check it out) etc.

Your statement and the headline are grammatically equivalent (minus your comma). However, the sentence is strange because “by” implies a causation that is not supported between the supposed cause and the supposed effect. The Neanderthals were brought to the cave to be eaten; it’s almost but not quite backwards.

My guess is what the author means is, “By preying upon...” which would be correct because dragging them to the cave is part of their predation. “By eating them” implies they were eaten and then, because of the eating, wound up in the cave (say through defecation or inside the stomachs of dead hyenas).

As 'drops says, your versions is correct if you drop the comma. You can move parts of a sentence around from the "normal" order with commas:

    Normal:          Hyenas gathered 9 Neanderthal skeletons by eating them.
    Move with comma: By eating them, hyenas gathered 9 Neanderthal skeletons.

    Normal:          I think it will rain later.
    Move with comma: It will rain later, I think.

Could also get weird and stuff it in the middle.

>Hyenas gathered, by eating them, 9 Neanderthal skeletons.

Which is even more awkward in actual use, but does make obvious the biggest problem with the sentence: you don't gather things by eating them.

It's an awkward headline for sure.

"Neanderthal skeletal remains found in hyena lair". It's simple and straightforward. Explain the why in the article. Don't try to explain everything in a headline.

It is strange and it probably was chosen to stand out and draw more attention.