Data for optimizing energetics of lateral undulatory locomotion unveiling morphological adaptations in different environments

Ongoing efforts seek to unravel theories that can make simple,
quantitative, and reasonably accurate predictions of the morphological
adaptive changes that arise with the size variation. Yet, relatively scant
attention has been directed towards lateral undulatory locomotion. In the
current study, we explore: i) the constraints imposed by the variation of
length and mass in viscous and dry friction environments on the cost of
transport (COT) of lateral undulatory locomotion, and ii) the role of the
body, environment, and input oscillations in such an intricate interplay.
In a dry friction environment, minimum COT correlates with stiffer and
longer bodies, higher frictional anisotropy, and angular amplitudes
greater than 10o. Conversely, a viscous environment favors flexible long
bodies, higher frictional anisotropy, and angular amplitudes lower than
30o. In both environments, optimizing mass and maintaining low angular
frequencies minimizes COT. Our conclusions are applicable only in the low
Reynolds number regime, and it is essential to consider the
interdependence of parameters when applying the generalized results. Our
findings highlight musculoskeletal and biomechanical adaptations that
animals may use to mitigate the consequences of size variation and to meet
the energetic demands of lateral undulatory locomotion. These insights
enhance foundational biomechanics knowledge while offering practical
applications in robotics and ecology.