Metal

On our bicycling route to work there is one house we pass that has a small screened-in porch. On that porch are two large dogs, I haven’t seen them because of the way the porch is situated, but they sound large and I’m glad they are kept inside. Definitely on the way to work and most times on the way home, we are the only traffic on the road this house is on, but we can not get within 25 yards of it before the dogs start barking. They bark continuously until we are probably 25 yards down the road past them. We are not usually talking at this point in the ride, it is flat so we aren’t doing any gear shifting, we are just pedaling along with the only sound being the whir of the chain and invariably those two dogs start raising a ruckus long before we get anywhere near them.

I think James Cameron must have been a bicyclist and had similar experiences with dogs hearing him coming a long way off because he includes a bit in the Terminator movies about humans using dogs to detect the cyborgs (AKA Metal.) If dogs can hear a component of the high pitched bicycle chain noise from a ways off it stands to reason that they also can pick up the sound of a motor moving a metal joint encased in a layer of human flesh.