For some reason this immediately reminded me of Larry Nivens Draco Travern: "The Slow Ones". Were a race of aliens had a much slower metabolism than ours, they

For some reason this immediately reminded me of Larry Nivens Draco Travern: "The Slow Ones". Were a race of aliens had a much slower metabolism than ours, they looked like rocks that slowly over decades where moving toward the tavern across the field to visit. You could communicate with them through email get replies back after a couple of months, to the aliens it was basically instant messaging.