Too arid to support cattle ranching, so it must be sheep farting.
There are a lot of cows out there, just not a lot of cows per square mile. My old stomping grounds.
BTW, I had more than one client show me how they could light the water in their sink. This was long before fracking.
One guy collected the gas and used it to cook on. He didn’t have enough volume to heat his house with, though.
Not much human civilization in that area.