I have just received confirmation that I have taken the only known photographs of a Mongolian argali sheep crossing a river. This occurred at the Gun-Galuut Nature Reserve during my Flag Expedition on the very first morning of observations. In fact, he (Dr. Reading believes it was a yearling ram) was one of four of the first argali I saw on the trip.
Dr. Reading also noted in his reply to my query that “Well, I don’t think anyone ever doubted that argali cross these relatively shallow, relatively slow rivers (at least I never did). All ungulates (and most mammals) swim pretty well and you need something a LOT more substantial that the Kherlen River to stop them.”
The main reason, I believe, that no one has gotten photographs is that the only place where argali have been studied in any depth is at the Ikh Nartiin Chuluu Nature Reserve, which has a few small streams, but no rivers. Research has begun at Gun-Galuut and, in fact, an Earthwatch team is scheduled to be there for part of their time in September, but the emphasis has been on capturing and putting radio collars on the argali, not behavioral observations.
The four sheep that I watched were on the opposite side of the river from their home range, Mt. Baits. Their behavior appeared anxious and finally one bolted back across the river. He climbed up on a high point and looked back. The young ram finally turned and ran back up onto the mountain. The other three argali seemed indecisive and ultimately did not cross, but moved up onto a smaller mountain where I finally lost sight of them.
Here are detail shots of the main three photos: