Foot disease is highly prevalent in both domestic and captive mammals, presenting a significant welfare problem with major economic losses. Although the causes are multifactorial, the interaction of the foot with the ground and control of foot impact are key factors. Impact transients, caused by the change in momentum at contact are potentially destructive. We speculate that although amplitudes are unlikely to exceed failure stress, high frequency (non-physiological) transient components will cause fatigue damage. To investigate this, we compared impact parameters in ungulate mammals spanning over three orders of magnitude in body size and characterised how impact transients and other aspects of foot mechanics change with animal size. Standard force-platform (1000Hz; Kistler) and motion capture (250Hz; Qualisys) methods measured 2D limb kinematics and kinetics across five species ranging from ~30kg (common sheep, O. aries) to ~3000kg (Asian elephants, E. maximus). We consider mechanisms of impact attenuation, active muscle dampening, altered geometry (foot deformation, joint/segment angles), altered leg stiffness and changes in velocity, loading rate and contact time. Our results show that controlling limb impacts during locomotion is a major constraint on locomotor form and function in feet. Understanding the mechanics and control of foot impact and their relationship with animal size, foot morphology and behaviour may improve our ability to identify, prevent and treat foot disease.