Regulating, braking and pushing mechanisms of reindeer (Rangifer tarandus) feet based on center of pressure

Reindeer are seasonal migratory animals, and their feet play a significant role in braking and pushing. Their natural habitats in arctic regions require them to navigate complex ground conditions, and their feet have evolved to adapt to these challenges. Reindeer must travel long distances to find food and water, which demands high levels of endurance and stamina. The ability of reindeer feet to support their weights and maintain stability over extended periods is crucial to the survival of reindeer. The center of pressure at different speeds (walking, low-speed trotting, and high-speed trotting) was studied using a pressure plate to determine the functions of the dewclaws, medial toes and lateral toes of reindeer. The medial toes and lateral toes were the bearing toes, and the dewclaws played an auxiliary supporting role. The proportions of peak value in the bearing toes and dewclaws were 85.1-9.5% and 2.7-22.9%, respectively. The center-of-pressure trajectories of hindfeet and forefeet were an L-shaped line and a straight line, respectively. The proportion of peak value in forefoot dewclaws (7.0-22.9%) was larger than that of hindfoot dewclaws (2.7-8.2%). The coefficients of variation of forefoot dewclaws increased with rising speed, indicating the forefeet adjusted the pressure according to the motion state. The coefficient of variation of forefoot dewclaws (31.1-73.1%) was larger than that of bearing toes (14.1-40.7%), indicating the dewclaws played a stabilization role. The pressure on the bearing toes of the forefeet, which played a braking role, increased with time during the braking phase. The peak loads on the distal medial toe and the distal lateral toe of hindfeet were both in the pushing phase, which were mainly associated with a pushing role. Hence, the characteristics of reindeer feet are conducive to improving the stabilizing and migrating abilities.