Study: Sharks have mammal-like muscles

October 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: Why do shark bites seem to be more deadly in Australia than elsewhere?

Related Stories

How Hot Tuna (and Some Sharks) Stay Warm

October 28, 2005

Scientists now have direct evidence that the north Pacific salmon shark maintains its red muscle (RM) at 68-86 degrees Fahrenheit, much warmer than the 47 F water in which it lives. The elevated muscle temperature presumably ...

Researchers discover deep sea sharks are buoyant

June 19, 2015

In a study published recently, scientists from the University of Hawai'i - Mānoa (UHM) and University of Tokyo revealed that two species of deep-sea sharks, six-gill and prickly sharks, are positively buoyant - they have ...

Recommended for you

Cells lacking nuclei struggle to move in 3-D environments

January 20, 2018

University of North Carolina Lineberger Comprehensive Cancer Center researchers have revealed new details of how the physical properties of the nucleus influence how cells can move around different environments - such as ...

Information engine operates with nearly perfect efficiency

January 19, 2018

Physicists have experimentally demonstrated an information engine—a device that converts information into work—with an efficiency that exceeds the conventional second law of thermodynamics. Instead, the engine's efficiency ...

Team takes a deep look at memristors

January 19, 2018

In the race to build a computer that mimics the massive computational power of the human brain, researchers are increasingly turning to memristors, which can vary their electrical resistance based on the memory of past activity. ...

Fast computer control for molecular machines

January 19, 2018

Scientists at the Technical University of Munich (TUM) have developed a novel electric propulsion technology for nanorobots. It allows molecular machines to move a hundred thousand times faster than with the biochemical processes ...

0 comments

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.