Toothed whale biosonar adjustments to the surroundings

PhD defence, Friday 25 August 2017. Michael Ladegaard.

2017.08.25 | Steffi Hjerrild Iversen

Michael Ladegaard

During his PhD, Michael Ladegaard has investigated how toothed whales adjust their biosonar to echolocation targets in different contexts and how these biosonar systems are adapted to the habitats in which the animals live. This research has highlighted how the Amazon river dolphin that lives in shallow-water river systems and flooded forests, use a directional, short-range biosonar that is operated at two to four times the update rates compared to dolphins in marine environments. In addition, Michael Ladegaard has studied how bottlenose dolphins use an almost unknown echolocation mode when echolocating targets at ranges of several hundred metres and how harbour porpoises handle interfering echolocation clicks produced by conspecifics that make it difficult to discern the few returning echoes relating to the porpoises’ own clicks.

This research has led to an increased understanding of how toothed whale echolocation operates in several hitherto poorly studied areas. Additionally, Michael Ladegaard has contributed with a critical approach of how to interpret especially data collected on wild toothed whales in relation to the limitations that exists for the recording systems that scientists generally use.

The PhD degree was completed at the section for Zoophysiology, Department of Bioscience, Science and Technology, Aarhus University.

This résumé was prepared by the PhD student.

Time: Friday 25 August 2017, at 10.15
Place: Building 1110, Room 223, Bioinformatics Research Centre (BIRC), Aarhus University, C. F. Møllers Allé 8, 8000 Aarhus C  
Title: Echolocation in small cetaceans
Contact info: Michael Ladegaard, e-mail:, tlf.: 4076 4035
Members of the assessment committee: 
Professor Cynthia Moss, Department of Psychological & Brain Sciences, Johns Hopkins University
Senior researcher Sander Von Benda-Beckmann, TNO, Netherlands organization for Applied Technological Research
Professor Angela Fago, Department of Bioscience, Aarhus University (chair) 
Main supervisor: 
Professor Peter Teglberg Madsen, Zoophysiologi, Department of Bioscience, Aarhus University 
Language: The PhD dissertation will be defended in English

The defence is public.
The dissertation is available for reading at the Graduate School of Science and Technology/GSST, Ny Munkegade 120, building 1520, rooms 128-134, 8000 Aarhus C.

PhD defence
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Revised 23.02.2018