According to a report, the sharks may be able to maintain their body temperature in the icy waters by reducing the activity of their gills while they are submerged. This results in the sharks "holding their breath" for periods of up to an hour at a time.
Sharks do not breathe air, but when they dive deep, they may seal their mouths and gill slits to regulate body temperature as they go from warmer water near the surface to cooler water below. The study's principal author, Mark Royer of the Hawai'i Institute of Marine Biology's Shark Research Group, said that though it's apparent that marine mammals that air-breathe can retain their breath while diving, but sharks doing the same surprised us. Royer believes scalloped hammerhead sharks eat like marine mammals.
Sphryna lewini, or scalloped hammerheads, are big sharks that are endangered worldwide. They are threatened elsewhere but not in Hawaii, mostly due to habitat loss, exploitation, and unintentional capture. Sharks are ectothermic, therefore water temperature controls their body temperature. Despite living in shallow coastal areas with subtropical or tropical weather, hammerheads have been seen swimming to depths of almost 3,400 feet, where the water temperature can approach 40 degrees Fahrenheit. Tracking sharks required implanting biologgers. Devices track shark behaviors, temperatures, depths, and water temperatures. Biologgers reveal deep-sea animals.
"An ongoing technological revolution in tagging, of which the Royer et al. study is a part, is likely to reveal other insights into the physiology and ecology of sharks that may explain how these animals have survived 400 million years of changing ocean environments," Mark Meekan and Adrian Gleiss, marine biologists who were not involved in the recent paper, wrote in an accompanying Perspectives article. Sharks averaged 17 minutes without breathing. After four minutes, they returned to shallower waters. Royer claimed sharks' bodies could protect them against climate change and deep sea fishing and digging. Animals breathe less. As shown, Homo sapiens' sins harm all animals.
