Nicholas Whitney of Mote Marine Laboratory in Sarasota, Fla., and colleagues observed that nurse sharks are some of the most inactive species of shark that spend most of their time on the ocean bottom waiting in one spot. They only move at night when they have to hunt for food. This behavior interested the researchers in understanding how this affected the shark’s metabolism. They studied eight young nurse sharks and measured their respiration at different times of the day and at different water temperatures to determine the metabolism rate. It was found that the sharks had a slower metabolism than any of the shark species that breathe through ram ventilation i.e. who keep their mouths open while swimming to prevent the water from flowing across the gills. The researchers concluded that due to the slow metabolism, any activity such as catching prey costs them energy, which is probably why they remain inactive most of the time.
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