Study: Sharks have mammal-like muscles

Oct 26, 2005

University of British Columbia scientists say some sharks have swimming muscles that only work at relatively high temperatures -- much as do mammals' muscles.

Robert Shadwick and colleagues studied salmon sharks, which spend their lives in the chilly waters of the North Pacific. The scientists discovered that unlike most other fish, the sharks rely on heat generated within their muscles to maintain their constant swimming.

They discovered that "red muscles" -- which power the sharks' constant swimming and are found at the body's core -- had a temperature of up to 26 degrees Celsius, some 20 degrees warmer than the sea water.

The researchers say their discovery shows how specialized the sharks are for their predatory lifestyle. The red swimming muscles rely on heat produced during muscular contraction to work efficiently. If their temperature were allowed to drop to that of the surrounding water, the sharks would not be able to swim.

In contrast, the salmon's 'white muscles' -- which are used for bursts of speed -- work well across a range of temperatures, the researchers added.

The study is detailed in the current issue of the journal Nature.

Copyright 2005 by United Press International

Explore further: How racial stereotypes impact the way we communicate

Related Stories

New research reveals first warm-blooded fish

May 14, 2015

New research by NOAA Fisheries has revealed the opah, or moonfish, as the first fully warm-blooded fish that circulates heated blood throughout its body much like mammals and birds, giving it a competitive ...

Remoras don't suck

Feb 12, 2015

How does the hitchhiking, flat-headed remora fish attach to surfaces so securely yet release so easily? Suction was thought to be the easy answer, but Brooke Flammang, a biologist at the New Jersey Institute ...

Studying the Noble King Mackerel

May 24, 2013

They are sometimes called "smokers," due to the speed at which a fishing line zips out the reel and "smokes" after they hit on the bait.

Recommended for you

Rewriting the history of the Boaz mastodon

46 minutes ago

Through a combination of modern-day scientific sleuthing, historical detective work, and a plethora of persistence, researchers at the University of Wisconsin-Madison have rewritten the story of a celebrated ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.