Hammerhead Sharks Use 'Breath Holding' to Stay Warm During Deep Dives

Scalloped hammerhead sharks hold their breath for about 17 minutes to stay warm during hunting dives in cold water.
These sharks venture into deep, chilly water to hunt, which is problematic because they are cold-blooded.
The sharks were making steep, fast descents to spend a few minutes feasting in deep waters, then speeding most of the way back to the surface.
The researchers think the mystery lies in the sharks’ gills, which they believe the sharks are closing during their daring dives.
Scalloped hammerhead sharks may not be unique in employing this technique for deep dives.