According to the passage, why isnt a blue whale lonely when it travels alone?

* Hướng dẫn giải

Dẫn chứng: However, the blue whale has the most powerful voice in the animal kingdom and its low-frequency sounds can travel in deep water over  hundreds, or even thousands, of miles. Under these circumstances, animals which may appear to us to be traveling alone may actually be in constant contact with one another.