This method does not work very well for sharks since most of them lose their teeth every seven to 21 days. Just recently, marine biologists began tagging or tracking some shark species. Early research shows that slow growing sharks, such as the tope shark and the piked dogfish, can live more than 40 years. I read sharks can eat once a month and still live. Scientists at Sea World have learned that a shark eats about one percent to 10 percent of its total body weight per week.
Humans use food to generate body heat.
Since sharks are cold blodded, they don't need food to ehat their body. Some sharks are filter feeders. The basking shark and megamouth shark strain huge amounts of plankton from the water on gill rakers. Whale sharks also filter feed. They strain plankton through a spongy tissue in their mouth.