SUMMARY
Toothed whales and dolphins possess a hypertrophied auditory system that allows for the production and hearing of ultrasonic signals. Although the fossil record provides information on the evolution of the auditory structures found in extant odontocetes, it cannot provide information on the evolutionary pressures leading to the hypertrophied auditory system. Investigating the effect of hearing loss may provide evidence for the reason for the development of high-frequency hearing in echolocating animals by demonstrating how high-frequency hearing assists in the functioning echolocation system. The discrimination abilities of a false killer whale (Pseudorca crassidens) were measured prior to and after documented high-frequency hearing loss. In 1992, the subject had good hearing and could hear at frequencies up to 100 kHz. In 2008, the subject had lost hearing at frequencies above 40 kHz. First in 1992, and then again in 2008, the subject performed an identical echolocation task, discriminating between machined hollow aluminum cylinder targets of differing wall thickness. Performances were recorded for individual target differences and compared between both experimental years. Performances on individual targets dropped between 1992 and 2008, with a maximum performance reduction of 36.1%. These data indicate that, with a loss in high-frequency hearing, there was a concomitant reduction in echolocation discrimination ability, and suggest that the development of a hypertrophied auditory system capable of hearing at ultrasonic frequencies evolved in response to pressures for fine-scale echolocation discrimination.
FOOTNOTES
-
This research project was supported by the Office of Naval Research (Grant NOO14-08-1-1160 to P.E.N.), for which the authors thank Jim Eckman and Neil Abercrombie. Work was approved under the University of Hawaii Institutional Animal Care Committee Protocol No. 93-005-15. The authors also thank all the members of the Marine Mammal Research Program group, including Alexander Supin and Whitlow Au, for their continuous assistance; and Tom Lane at MathWorks for programming and statistical assistance. This is contribution no. 1409 from the Hawaii Institute of Marine Biology.
- © 2010.
Article navigation
Related articles
Cited by...
More in this TOC section
Similar articles
Other journals from The Company of Biologists
Editorial – The changing of the guard
In his Editorial, Hans Hoppeler announces that he will be stepping down as Editor-in-Chief of JEB in July 2020. He reflects on the history of JEB, why he has enjoyed his tenure as JEB’s Editor-in-Chief and the recent developments in the publishing world.
Editors’ choice – Parental stressor exposure simultaneously conveys both adaptive and maladaptive larval phenotypes through epigenetic inheritance in the zebrafish (Danio rerio)
An oil spill is never a good thing, but Naim Bautista and Warren Burggren have shown that zebrafish can pass on resistance to the damaging effects of an oil-spiked diet to their offspring.
The derivative of force with respect to time does not have a standard term in physics. In their new Commentary, David C. Lin and his colleagues propose that the term ‘yank’ should be used to denote the time derivative of force.
Runners waste energy every time their legs stop swinging, but now a team of scientists from the US and Canada have shown that a springy ankle tether can reduce runners’ energy costs by 6.4%, which is nearly the entire cost of swinging the limbs. Read the full research article here.
Journal of Experimental Biology is pleased to announce a new partnership with Publons! This allows reviewers to easily track and verify every review by choosing to add the review to their Publons profile when completing the review submission form. Publons also makes it simple for reviewers to showcase their peer review contributions in a format that can be included in job and funding applications (without breaking reviewer anonymity). Read the official announcement here!
The Company of Biologists provides grants to fund scientific meetings, workshops and conferences in the fields covered by our journals. Typically, meetings with fewer than 100 people may be granted up to £2,000, increasing up to £6,000 for about 400 people. The next deadline to apply is 28 November 2019.
preLights – preLights reaches 500 posts!
The success of preLights is down to the hard work of our preLighters. Head over to the preLights website to find out more about our most active early-career-researchers.