Social Transmission of Fear in Rats: The Role of 22-kHz Ultrasonic Distress Vocalization Kim, Eun Joo ; Kim, Earnest S. ; Covey, Ellen ; Kim, Jeansok J. Abstract Publication: PLoS ONE Pub Date: December 2010 DOI: 10.1371/journal.pone.0015077 Bibcode: 2010PLoSO...515077K