Hammerhead sharks are warm water animals, yet some were filmed diving to depths of over 1,000 meters, where the water is about 5 degrees Celsius. In order to keep warm the sharks hold their breaths, keeping their gills closed, and by that, they prevent the heat from running out of their body. Once they are back at the surface they release their gills and their body temperature goes down.
Photo by: https://www.pexels.com/photo/hammerhead-shark-swimming-near-corals-4781942/
