Their legs extend beneath their body rather than to the side 它们的腿长在身体下方而非侧面

300. They have a much more efficient breathing system
     它们拥有一种更高效的呼吸系统
301. that continuously pumps blood across their lungs...
     能够持续将血液送至肺部
302. allowing them to run without having to stop to catch their breath.
     使其在奔跑时无需停下来呼吸
303. Their legs extend beneath their body rather than to the side
     它们的腿长在身体下方而非侧面
304. so they can walk upright.
     所以可以直立前行
305. This allows tiny hatchlings to grow
     这使小小的幼崽能够长大
306. into adults that are 50 times their size.
     成为体重是自己50倍的成年动物

来自《我们星球上的生命 第一季 第四集 Life on Our Planet S01E04 冷血动物》第 303 行