restricted to feeding on low-energy kelp... 只能以低能量的海藻为食

348. Scanning for fish, it hovers like a hummingbird...
     寻找鱼类时 它们像蜂鸟一样
349. with perfect poise.
     完全悬停
350. In contrast, the cold-blooded iguanas are slow and sluggish...
     相比之下 冷血的海鬣蜥动作迟缓
351. restricted to feeding on low-energy kelp...
     只能以低能量的海藻为食
352. at the whim of the currents.
     还要看洋流的脸色
353. The warm-blooded penguins couldn't be more different...
     温血的企鹅则完全不同
354. with their speed and agility...
     凭借其速度和敏捷度

来自《我们星球上的生命 第一季 第六集 Life on Our Planet S01E06 灰烬中重生》第 351 行