was a group of warm-blooded animals 有一群温血动物

193. The greatest of them all, reaching over 100 meters into the air,
     其中最大的 高度超过100米
194. were the redwoods.
     红杉
195. Sheltered beneath the forests
     在森林的庇护之下
196. was a group of warm-blooded animals
     有一群温血动物
197. that had long hidden in the shadows.
     长♥期♥隐藏在阴影之中
198. The mammals.
     哺乳动物
199. At first, they were small creatures,
     起初 它们是小型生物

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 196 行