Abstract
Water bears (tardigrades) are microscopic crawlers with body lengths of 100 μm order that walk on four pairs of stubby, tubular and clawed legs without any joints called the first, second, third and fourth legs. The gait of water bears is mechanically interesting because it is unusual that such a small microorganism walks on four pairs of legs. In this study, the gait of water bears with different walking speeds was analyzed and the features of the gait were investigated. Twenty-two water bears (Milnesium tardigradum) with body lengths between 0.204 and 0.598 mm, which were obtained from Miyashiro town (Saitama, Japan), were used as samples. The results were as follows. The water bears tended to have the tripod gait for faster walking speeds, the wave gait for slower speeds and the ripple gate for intermediate speeds. These results indicated that the gait of water bears is similar to that of insects. During the directional change, the third and fourth legs supported the body, and the first and second legs were used to change the direction of movement.
