FOREFLIPPER PROPULSION IN THE CALIFORNIA SEA LION, ZALOPHUS-CALIFORNIANUS
FOREFLIPPER PROPULSION IN THE CALIFORNIA SEA LION, ZALOPHUS-CALIFORNIANUS
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DOI：
10.1111/j.1469-7998.1987.tb05113.x
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发表时间：
1987-05-01
影响因子：
2
通讯作者：
FELDKAMP, SD
中科院分区：
文献类型：
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作者：
FELDKAMP, SD
鳍足科是海洋哺乳动物中唯一一种在游泳时习惯使用胸肢产生推进力的动物。这种推进方法在加利福尼亚海狮（Zalophus californianus）身上得到了检验，它是该家族的代表成员。拍摄高速电影时，一只海狮在一个大的水流通道内逆流而上。推力产生是通过检查机体在推进循环的各个阶段的运动来确定的。海狮在划水过程中不断产生推力。在最初的四分之三，前鳍起到水翼的作用，在水中垂直移动时产生向前的推力和升力。然而，在接近行程结束时，当桨叶用作桨，并且面向迎面而来的流时，推力产生更大。这种三相推进系统产生的力量可能比完全基于升力的水翼或基于阻力的划桨游泳方式所能达到的更大。研究人员还研究了使海狮能够改变速度的运动学变化。胶片记录显示，虽然总冲程振幅随速度增大而增大，但总冲程持续时间基本保持不变。海狮随着速度的增加而增加划水频率，但测量值的巨大变化表明，振幅和鳍攻角的变化也是调节游泳速度的重要参数。
The family Otariidae comprises the only group of marine mammals that habitually use their pectoral appendages to generate propulse forces during swimming. This method of propulsive was examined in the California sea lion (Zalophus californianus), a representative member of the family. High-speed films were taken as a sea lion swam against a water current generated inside a large flow channel. Thrust production was determined by examining the body''s movement at various stages of the propulsive cycle. Sea lions generate thrust continuously throughout the stroke. Over its initial three-quarters, foreflippers act as hydrofoils creating forward thrust and lift as they move vertically through the water. Thrust production is greater, however, near the end of the stroke, when flippers are used as paddles and are oriented broad side to the oncoming flow. The force generated by this three-phased system of propulsion is likely to be greater than that attainable by either an exclusively lift-based hydrofoil or drag-based paddling style of swimming. The kinematic changes that enable sea lions to change speed were also investigated. Film records revealed that stroke amplitude became greater with speed, although total stroke amplitude became greater with speed, although total stroke duration remained essentially constant. Sea lions increase stroke frequency with velocity but large variations in the measured values suggest that changes in amplitude and flipper angle of attack are also important parameters for modulating swimming speed.