Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, RI 02912, USA.
Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA.
J Exp Biol. 2024 Apr 15;227(8). doi: 10.1242/jeb.247042. Epub 2024 Apr 22.
Large and stout snakes commonly consume large prey and use rectilinear crawling; yet, whether body wall distention after feeding impairs rectilinear locomotion is poorly understood. After eating large prey (30-37% body mass), all Boa constrictor tested could perform rectilinear locomotion in the region with the food bolus despite a greatly increased distance between the ribs and the ventral skin that likely lengthens muscles relevant to propulsion. Unexpectedly, out of 11 kinematic variables, only two changed significantly (P<0.05) after feeding: cyclic changes in snake height increased by more than 1.5 times and the longitudinal movements of the ventral skin relative to the skeleton decreased by more than 25%. Additionally, cyclic changes in snake width suggest that the ribs are active and mobile during rectilinear locomotion, particularly in fed snakes, but also in unfed snakes. These kinematic changes suggest that rectilinear actuators reorient more vertically and undergo smaller longitudinal excursions following large prey ingestion, both of which likely act to reduce elongation of these muscles that may otherwise experience substantial strain.
大型粗壮的蛇类通常会捕食大型猎物，并采用直线爬行方式；然而，进食后身体壁的膨胀是否会影响直线运动，目前还不太清楚。在进食大型猎物（占体重的 30-37%）后，所有接受测试的巨蟒都可以在有食物团块的区域内进行直线运动，尽管肋骨和腹侧皮肤之间的距离大大增加，这可能会延长与推进相关的肌肉。出人意料的是，在 11 个运动学变量中，只有两个在进食后发生了显著变化（P<0.05）：蛇身高度的周期性变化增加了 1.5 倍以上，腹侧皮肤相对于骨骼的纵向运动减少了 25%以上。此外，蛇身宽度的周期性变化表明，肋骨在直线运动中是活跃且可移动的，尤其是在进食后的蛇类中，但在未进食的蛇类中也是如此。这些运动学变化表明，直线驱动器在进食大型猎物后会更垂直地重新定向，并进行更小的纵向伸展，这两者都可能会减少这些肌肉的伸长，否则这些肌肉可能会受到很大的拉力。
