But to 19th-century naturalists such as Charles Darwin, these air-breathing, warm-blooded animals that nurse their young with milk distinctly grouped with mammals.
But to 19th-century naturalists such as Charles Darwin, these air-breathing, warm-blooded animals that nurse their young with milk distinctly grouped with mammals.
但是对19世纪的博物学家，像是达尔文，鲸豚是呼吸空气的温血动物，并以乳汁抚育幼儿，当然属于哺乳类。