Length of Orca Dives

From: Nancy Stevick (Nancy.Stevick@btinternet.com)
Date: Thu Feb 10 2000 - 15:49:38 EST


On 10 February 2000, Shaun and his Dad wrote:
    Subject: Orca
    
    
    Hi, my son is doing some research for a school project about Orca's and we were just wondering how long an Orca can stay under water?
    
    Thanks,
    
    Shaun and Dad :)
    
    Dear Shaun and Dad,
    
    Whales dive in order to pursue their food, so the behaviour of prey determines how long the whales stay underwater. Orcas generally feed on prey fairly near the surface, so they don't have to dive for long periods of time. In fact, some orcas actually beach themselves in order to haul sea lions off the shore!
    
    We are not certain just how long an orca could remain submerged, but we do have information on animals that have been radio tagged. These tags can be used to measure the length and depth of dives. In one study, two radio tagged orca had a mean (average) dive cycle of 5.77 minutes and a maximum dive time of 17 minutes. The maximum depth of dive reported from a wild orca is 173 meters and for a trained animal it is 260 meters.
    
    The above information is all from Dalheim and Heyning, 1999. The killer whale. Pages 281-322 in the Handbook of Marine Mammals Volume 6.
    
    Seventeen minutes does not seem like a long time for a whale to remain submerged, and these whales could probably stay under for much longer. The point is, they did not need to, so they didn't.
    
    I hope this answers your question and helps complete Shaun's research.
    
    Cheers,
    Nancy



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