copyright JakenMax

Fishin' for Facts: How can marine mammals hold their breath for so long? 

©WhaleTimes

WhaleTimes gets this question often, so we thought we'd make the answer available for every one. Hope it helps, Jake, the SeaDog

Whales and other marine mammals have special adaptations that allow them to hold their breath longer than a person. Believe or it not, though, breath holding isn’t the key -- oxygen conservation and storage is. Seals have so much oxygen in their body, you might be surprised to learn they actually exhale before they dive!

Some of the ways marine mammals conserve or store oxygen include:

bulletReduced heart rate: When a marine mammal dives its heart rate slows down to conserve oxygen. Some drop from 120 beats per minute to 4 to 6 beats.
bulletCarrying oxygen: Marine mammals have a high concentration of oxygen-carrying cells in their muscles and blood.
bulletMore blood equals more oxygen: Marine mammals have two to three times more blood than a human. Other adaptations also include a network of spiral blood vessels that act as reservoirs for oxygen rich blood. And, seals and sea lions store oxygenated blood in their extra-large spleen (which can be 45% of their body weight).
bulletRecirculating the blood: For extended dives the blood is shunted or recirculated to only the most essential organs, like the heart, lungs, and brain. How long a marine mammal stays underwater depends on the species, where it lives, and what it eats.

Here are some examples of average diving times: A male Northern elephant seal’s dive is about 20 to 35 minutes, a harbor seal -- 3 to 7 minutes, and a walrus -- 10 minutes. A bottlenose dolphin may stay under 8 minutes, a killer whale 10 minutes, an Amazon river dolphin can stay under only 2 minutes.

Tidbit: Seals’ diving capabilities are often underestimated. The breath holding ability of most seals is greater than most whales.

 

Citation: Musgrave, Ruth A. How can marine mammals hold their breath for so long? Fishin' for Facts. WhaleTimes, Inc. (whaletimes.org) 2011

Back to the Fishin' for Facts page

Back to WhaleTimesAsk Jake, the SeaDogBack to the KidsPage

WhaleTimes, Inc. is a nonprofit 501(c)(3) corporation. Find out how to support WhaleTimes education programs.

About WhaleTimes

Copyright 2009-1995 WhaleTimes, Inc. All Rights Reserved. No portion of this website can be used in any other works without written permission of WhaleTimes, Inc.