【英语时差8,16】独角鲸（下）

（单词翻译）

 Researchers from Harvard’s School of Dental Medicine think the giant tooth might also act as a sensory¹ organ. With an electron microscope they discovered that the surface of a narwhal tusk² is covered with millions of tiny nerve endings. These nerves connect to the narwhal’s brain through a network of tiny tubes in the tooth. The scientists believe that the narwhal use the sensitive tusks³ to detect changes in temperature, salt content, and flow patterns in the environment around them. But since only males grow tusks, it’s likely that the tusks did not evolve primarily as a sensory organ. More research is needed to really understand why narwhals have tusks and how they use them.