Range-dependent flexibility in the acoustic field of view of echolocating porpoises (Phocoena phocoena)

Elife. 2015 Mar 20;4:e05651. doi: 10.7554/eLife.05651.

Abstract

Toothed whales use sonar to detect, locate, and track prey. They adjust emitted sound intensity, auditory sensitivity and click rate to target range, and terminate prey pursuits with high-repetition-rate, low-intensity buzzes. However, their narrow acoustic field of view (FOV) is considered stable throughout target approach, which could facilitate prey escape at close-range. Here, we show that, like some bats, harbour porpoises can broaden their biosonar beam during the terminal phase of attack but, unlike bats, maintain the ability to change beamwidth within this phase. Based on video, MRI, and acoustic-tag recordings, we propose this flexibility is modulated by the melon and implemented to accommodate dynamic spatial relationships with prey and acoustic complexity of surroundings. Despite independent evolution and different means of sound generation and transmission, whales and bats adaptively change their FOV, suggesting that beamwidth flexibility has been an important driver in the evolution of echolocation for prey tracking.

Keywords: beam directionality; biosonar; buzz; convergent evolution; ecology; neuroscience; phocoena phocoena; prey capture.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological
  • Animal Structures / anatomy & histology
  • Animal Structures / physiology*
  • Animals
  • Biological Evolution
  • Chiroptera / anatomy & histology
  • Chiroptera / physiology*
  • Echolocation / physiology*
  • Feeding Behavior / physiology
  • Female
  • Magnetic Resonance Imaging
  • Male
  • Phocoena / anatomy & histology
  • Phocoena / physiology*
  • Predatory Behavior / physiology
  • Sound
  • Video Recording
  • Vocalization, Animal / physiology*

Grant support

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.