Direct Interaction Between Roe Deer and Mountain Hare, a Case of Interference Encounter Competition?

Roe deer and mountain hares are known to select the same food sources and engage in indirect exploitative competition. Here we report on a case of direct interaction between a roe deer doe and a mountain hare recorded by a camera trap in Tydal Municipality, Norway, a possible case of direct interference competition. The roe deer doe is at least following and displacing the mountain hare for 2 min and 29 s, including a 19 s active chase phase. The two animals can be seen circling in and out of frame in front of the camera. This direct interaction is based on the limited information gained through the picture series. It could be a case of curiosity; however, we speculate that this is a case of interference encounter competition between these two herbivore species. From the literature, roe deer and mountain hares are known to compete indirectly for forage; moreover, roe deer are known to behave aggressively towards other competing deer species. Our traditional textbook understanding of ecology is based on the common and the easily observable, not the rare and difficult to observe. This observation challenges our understanding of the interactions between roe deer and hares, as roe deer may compete directly with mountain hares over food resources.