Nurse Sharks’ “Sluggish Lifestyle” Works Well

Written by on February 5, 2016 in Marine Life, Sharks

Nurse sharks have the lowest metabolic rate measured in any shark, according to new research from Mote Marine Laboratory. This “sluggish lifestyle” likely contributed to the survival of the species over the last several million years.

Nurse sharks in the Bahamas. Photo credit: Emily Tripp.

Nurse sharks in the Bahamas. Photo credit: Emily Tripp.

When we picture sharks, most of us probably imagine the big, charismatic ones like great whites or makos. These guys are active predators that chase their prey. Nurse sharks, on the other hand, are pretty lazy predators. They wait under rocks and in crevices where they can snap up unsuspecting prey as it wanders by without expending much energy.

Nurse sharks are able to sit on the ocean floor and wait for meals because they are one of few species of sharks that can pump water across their gills — they don’t have to constantly swim in order to breathe.

To study their metabolism, the researchers measured the oxygen consumption of nurse sharks in sealed tanks. They found that the sharks’ average metabolic rate when swimming was only 18% of a mako shark’s metabolic rate.

“If we know about a shark’s metabolism — their basic energy needs — then we can start to estimate their energy use in the wild to better understand their impact on the ecosystem,” Dr. Nick Whitney, manager of the Behavioral Ecology and Physiology Program at Mote, explained in a news release. “Sharks are often the top predators in the food web, consuming a lot of calories from animals on lower levels. As such, they often have a larger impact on the balance of the ecosystem than other species. To better understand the ecosystems that we want to preserve, we need to better understand sharks.”

Whitney and the other study authors note that nurse sharks are some of the most abundant species in tropical and subtropical ecosystems, so it’s clear that this low-energy strategy works.

“With their low metabolic rate, nurse sharks are pretty lazy — but the interesting thing is that this can be a very successful strategy,” Whitney said. “Nurse shark populations are doing very well compared with many other shark species. Their low-energy strategy is not the only factor, but it is part of their success.”

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Copyright © 2016 by Marine Science Today, a publication of Marine Science Today LLC.

About the Author

About the Author: Emily Tripp is the Publisher and Editor of MarineScienceToday.com. She holds marine science and biology degrees from the University of Miami's Rosenstiel School of Marine and Atmospheric Science and a Master of Advanced Studies degree in Marine Biodiversity and Conservation from Scripps Institution of Oceanography. When she's not writing about marine science, she's probably running around outside or playing with her dog. .

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