Researchers recently estimated that the total mammal species count will rise from about 5500 now to 7500 by mid-century .
研究人员们最近估计,到本世纪中叶,哺乳类动物的物种数量将从目前的5500种上升至7500种。
Already dr teeling has contributed to a large project on the world 's smallest mammal , the bumblebee bat .
teeling博士已经投入一个关于世界最小的哺乳动物大黄蜂蝙蝠的庞大研究项目中。
This means it had specialized kidneys , and was probably the first mammal to swim the open ocean .
这就意味着它的肾脏专门用来喝咸水,它可能就是第一个游向海洋的哺乳动物。
Peek-a-boo : the waianae coast of oahu is a visiting area for many cetaceans , but the hawaiian spinner dolphins are the most common marine mammal seen off this coast .