We are aiming to determine how changes in snow properties influence the function of a key adaptation for Arctic animals - the evolution of a snowshoe foot. Whilst increases in foot area are well known to provide extra support during movement over snow there is currently no data examining the relationship between snow hardness and snowshoe effectiveness in birds. We will build a bespoke force testing rig that will enable us to use a known force to push preserved ptarmigan feet into snow of different properties to examine how function of these feet changes with differences in the snowpack. We will compare Svalbard ptarmigan feet with those from closely related mainline rock and willow ptarmigan and also to outgroups that do not display these adaptations. Our research will provide new and important information on the potential impact of a changing climate which will alter the physical properties of the snow.