Jumping in the Salamander Desmognathus ocoee
Unlike most terrestrial vertebrates, which use force generated from the hind limbs to jump, salamanders jump by laterally bending and then rapidly straightening the body, using momentum to carry the individual through the air. This movement is strikingly similar to both the terrestrial escape response of mudskippers and terrestrial blennies, and shares a general pattern of movement with the C-start escape response in several aquatic vertebrates. While the axial musculature appears to be responsible for this behavior, it remains to be seen what role the limbs and tail play. Across a two-fold range in body sizes, few kinematic parameters were correlated with size. The lack of strong scaling relationships suggests a spring mechanism that allows performance to be maintained despite a two-fold increase in size.
Individual D. ocoee with landmarks for digital analysis with scale. Point 1 indicates the pectoral girdle, point 3 is the pelvic girdle, and point 2 is equidistant between the two girdles.
Representative image sequence of jumping in the salamander, D. ocoee. Numbers in the left corner correspond to time, in milliseconds.
Bivariate plots with log axes to examine scaling relationships in three variables: Jump Distance, Bend Velocity, and Unbend Velocity. Gray lines are lines of isometry, as dictated by Hill (1950). Bend Velocity was the only variable with a significant scaling relationship. The solid black line is the slope of the regression, and the dashed lines indicate 95% confidence intervals for that slope. For Jump Distance and Unbend Velocity, the dotted line indicates the slope of the line that best fits the relationship.
Contributor Notes
Associate Editor: B. Stuart.