You would assume we'd copy this digestive track to convert grass to natural gas. May solve our fossil fuel crises. (Or at least alleviate it) A larger producer of methane by the way are termites. But they are considered part of the natural carbon cycle since we do not breed them. (So I hope) One of the theories is that the new ice age, that was till the 70's believed to be overdue, mass farming with cattle had it pushed back by the methane emissions.

Or we can do both.