They can feed their young whenever they choose, 它们可以随时喂养幼崽

48. Fortunately,
    幸运的是
49. mammals have evolved an extraordinary solution.
    哺乳动物 已经进化出一种非凡的解决方案
50. Milk.
    母乳
51. They can feed their young whenever they choose,
    它们可以随时喂养幼崽
52. even when food is scarce.
    甚至包括食物稀缺的时候
53. But milk wasn't the early mammals' only secret weapon.
    但是母乳并不是 早期哺乳动物唯一的秘密武器
54. They also had brain power.
    它们还拥有脑力

来自《我们星球上的生命 第一季 第七集 Life on Our Planet S01E07 地球继承者》第 51 行