you know that natural gas has no smell right? and that they put smell in it because it’s dangerous and you need to know if it’s leaking? well, do you know why they use that particular smell?
A retired engineer for Union Oil stated his company used turkey vultures to find gas leaks. Natural gas has no odor, but a substance is added to the gas so that leaks can be detected in pipelines, stoves, or furnaces. This substance, called ethyl mercaptan, is one of the chemicals emitted from carrion and thus attracts turkey vultures. Union Oil Engineers were sometimes able to find pipeline leaks by looking for turkey vultures circling above the gas lines [source]