He is forced to head out into deeper water. 它必须进入更深的水域
and the family will need to head out across the frozen sea before the mother's milk runs dry. 在母熊奶水干涸之前 一家人需要穿越冰封的海洋
giving them a head start when summer finally arrives. 这样可以顺利地迎接夏天的到来
They head towards their breeding grounds, almost 100 miles inland. 它们要前往繁殖地,几乎在离海岸100英里的内陆
and head down to the bottom of the gorge. 奔向峡谷底部
Receptors in the snake's head pick up the heat given off by the flying bats, 位于头部的“热眼”能觉察到 飞行中的蝙蝠散发出的热量
But sensory nodes on their head and body 可是它们头上和身上的感官突起
It's not so risky to put your head down 它们可以毫无顾虑地埋头吃草
But you need more than a head for heights to survive up here. 不过在这样的高度 要想活下去可不太容易
have given their chicks a head start. 因而它们的宝宝也有了领先的优势