I went for a walk along a forestry style track, yesterday. Ahead of me was a ewe, with two lambs. The ewe felt nervous about my approach, and started to trot away from me. The lambs were, of course, following her closely. However, the sheep didn't trot away uphill or downhill. Instead, they continued along the track. I also continued along the track. All of us walked in this procession for some time. As the sheep were moving faster, they increased the distance between us. In a short space of time, I could see the sheep about 1000m ahead of me.