A (the male) and I (the female) repeatedly mated on a tiny ledge that was hardly bigger than both of them on a shaley cliff...which was the entrance to their burrow. Had this not been so compatible, someone would have ended up in the river. And not all marmot pairings are compatible; just Saturday I watched a male (bowtie) try to mate with two females at a snow-covered Picnic colony and each attempt ended with snarls and bowtie jumping back. A and I, by contrast, were quite gentle and the matings were outside the burrow and didn't have a lot of obvious foreplay (just greetings and a lot of sitting together).
Fun stuff! Which will have to tide us over for a few days since a big spring storm has just arrived.