protect their builders from extremes of heat 保护着它们的主人

221. They're always built on a north-south axis,
     全部建成南北走向
222. which is why their builders are called compass termites.
     因此它们的建筑者被称为罗盘白蚁
223. These castles of clay
     这些粘土造就的城堡
224. protect their builders from extremes of heat
     保护着它们的主人
225. and seasonal floods experienced on many grasslands.
     不受草原酷暑和季节性洪水的伤害
226. Termites manage to do what most grass eaters can't,
     白蚁与大多数食草动物不同
227. break down dead grass and extract the nutrients.
     它们能分解枯草 提取养分

来自《行星地球 第二季 第五集 Planet Earth S02E05 草原》第 224 行