Killer whale (Orcinus orca) audiograms

• Published in: The Journal of the Acoustical Society of America 2016-10, Vol.140 (4), p.3298-3298
• Main Authors: Branstetter, Brian K., Acton, Doug, Stewart, John, Houser, Dorian, St. Ledger, Judy, Finneran, James, Jenkins, Keith
• Format: Article
• Language: English
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.4970488

Historically, understanding of killer whale (Orcinus orca) hearing was based on behavioral and evoked potential data from three animals, one of which had significant hearing loss. For the other two whales, the mean detection threshold at 20 kHz was 36 dB re 1 μPa; this is the lowest underwater behavioral detection threshold of any marine mammal tested, suggesting that it may be an outlier. The current study measured the behavioral audiograms of eight killer whales at two different facilities. Hearing sensitivity was measured from 100 Hz to 160 kHz in animals ranging in age from 12 to 52 years. Two whales had hearing loss consistent with presbycusis and a third displayed atypical low-frequency hearing loss (but normal high frequency hearing); previously measured low thresholds at 20 kHz were not replicated in any animal. Hearing in the killer whales was generally similar to other delphinids, with lowest threshold (49 dB re 1 μPa) at approximately 40 kHz, good hearing (i.e., within 20 dB of best sensitivity) from 5—80 kHz, and low- and high-frequency hearing cut offs (> 100 dB re μPa) of 600 Hz and 114 kHz, respectively.