Sharks can bend, swim, and maneuver in the ocean much differently than their bony fish counterparts (Photo by Dr. Greg Skomal).
Just like old uncle Frank, several species of sharks tend to become slower and less agile as they age, a new study from Florida Atlantic University has found.
In a a joint effort by FAU’s Charles E. Schmidt College of Science and the National Oceanic and Atmospheric Administration’s National Marine Fisheries Service, scientists examined cartilage mechanics from six species of sharks — the dusky shark (Carcharhinus obscurusp); the porbeagle (Lamna nasus); and charismatic sharks like the great white shark (Carcharodon carcharias); the shortfin mako (Isurus oxyrinchus) and the common thresher shark (Alopias vulpinus)–under biologically relevant conditions along the length of their bodies and over a range of ages.
Unlike humans and most land animals, sharks have mineralized cartilage skeletons instead of bones. This allows them to move at unbelievable speeds through the water. Since cartilage weighs less than bone and is less dense, sharks can bend, swim, and maneuver in the ocean much differently than their bony fish counterparts.
The study, which was published in the Journal of Experimental Biology, revealed that the youngest sharks were stiffer (able to resist compression) and tougher (able to absorb more energy) than older sharks, making them more nimble.
“Our results suggest that toughness and stiffness, which are positively correlated, may be operating in concert to support lateral body undulations, which is how a shark moves its body and tail from side-to-side to propel itself forward, while providing efficient energy transmission and return in these swift-swimming apex predators,” said Marianne E. Porter, Ph.D., co-author of the study and director of the Biomechanics Laboratory at FAU.
