美国科学60秒 SSS 2013-08-22(在线收听

   The lone wolf’s howl has long been chosen as a symbol of melancholy and loss. Now researchers have demonstrated that the choice was accurate. Howling is not related to the stress level of the crying canine or the dominance status of the departing wolf; the best predictor of a wolf’s howl is the closeness of the howler’s relationship with the wolf leaving its side. The study is in the journal Current Biology.

  The researchers separated individuals living in Austria’s Wolf Science Center. They recorded the resulting howls for 20 minutes after separation. Then the scientists took a sample of saliva from the howling wolves to measure circulating levels of cortisol, a hormonal stress indicator.
  Cortisol levels increased during all separations, whether a preferred partner or any other pack mate was taken away. But howling was much more pronounced when a close partner was removed
  The researchers thus concluded that the level of howling was determined by the relationship of the howler with the separated wolf, regardless of the removed wolf’s rank. Because even a wolf, apparently, can have a best friend.
  原文地址:http://www.tingroom.com/lesson/sasss/2013/08/227291.html