Killer whale Research > Killer whale acoustics

Killer Whale Acoustics.

Killer 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 behaviours and maintenance of group cohesion.	Listen to sound sample: Resident Calls
Pulsed calls can be categorized into highly stereotyped 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. They 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.	Listen to a sound sample: West Coast Transient Calls   Listen to a sound sample: West Coast Transient Whistles
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. By 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.	Listen to sound sample: West Coast Transient Echolocation     with Sound

Consortium Researchers are currently in the process of developing a protocol for the acoustic monitoring of transient killer whales. This project involves answering the following questions:


• How often do transient killer whales vocalize?
• In which context is vocal behaviour most common?
• Are vocalizations a useful tool to detect predation events
• How loud are the calls of transient killer whales?
• Over which distance can they be detected by the system?
  
  
  updated 27 February 2006