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MATLAB Handle GraphicsKiller whales extensively rely on sound for orientation, prey detection, and communication. Different types of sounds fulfill different functions for killer whales. Echolocation clicks, for example, are used for orientation and prey detection. Whistles are high-frequency sounds typically used by killer whales in social contexts, and pulsed calls are communicative sounds thought to play a role in the coordination of behaviors and maintenance of group cohesion.

listen Resident calls Listen to sound sample

MATLAB Handle GraphicsPulsed calls can be categorized into highly stereo typed call types. Different social groups within the same population have group-specific repertoires of different call types. As a result, resident killer whales in British Columbia and Alaska exhibit an intricate system of vocal dialects. The structure of these call types evolves slowly over time and is thought to be learned.Transient forms of killer whales, unlike their resident counterpart, rarely vocalize.

 Transient whistles Listen to a sound sample

MATLAB Handle GraphicsThey emit significantly fewer echolocation clicks and communicative calls than residents. Transients presumably vocalize less to avoid warning their prey. Indeed, marine mammals have excellent underwater hearing and typically escape at the sound of a transient’s underwater calls. Estimating the abundance of killer whales using the traditional ship survey method is costly, time consuming and logistically challenging. In many areas the effectiveness of ship surveys is further limited by impeding weather and sea conditions.

Transient calls Listen to a sound sample

MATLAB Handle GraphicsBy comparison, acoustically monitoring the movement of killer whales using remote hydrophones presents a relatively cheap and effective alternative. In addition, because calls are specific to different populations and social groups, the identity of the calling whale can be identified by vocal monitoring.Vocal monitoring can also provide information on predation rates in areas of marine mammal abundance given that transient killer whales usually become vocal after a marine mammal kill.

Transient echolocation Listen to sound sample

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