Certain fox species plunge-dive into snow to catch prey (e.g., rodents), a hunting mechanism called mousing. Red and arctic foxes can dive into snow at speeds ranging between 2 and 4 m/s. Such mousing behavior is facilitated by a slim, narrow facial structure. Here, we investigate how foxes dive into snow efficiently by studying the role of skull morphology on impact forces it experiences. In this study, we reproduce the mousing behavior in the lab using three-dimensional (3D) printed fox skulls dropped into fresh snow to quantify the dynamic force of impact. Impact force into snow is modeled using hydrodynamic added mass during the initial impact phase. This approach is based on two key facts: the added mass effect in granular media at high Reynolds numbers and the characteristics of snow as a granular medium. Our results show that the curvature of the snout plays a critical role in determining the impact force, with an inverse relationship. A sharper skull leads to a lower average impact force, which allows foxes to dive head-first into the snow with minimal tissue damage. Many animal species interact with the air–water interface ( 1, 2). Examples include gannets diving into water to catch their food ( 3), humans cliff diving for sport ( 4, 5), basilisks walking on the water surface ( 6), and dolphins porpoising ( 7). Accordingly, there have been studies about the mechanical properties and impact force of this air–water interface ( 8– 11). On the other hand, interaction with snow is mostly limited to the winter sports of ski jumping and freestyle skiing, where low friction of compacted snow is exploited to slide at high speeds. Thus, mechanics of animals or people penetrating the air-snow interface is less known.