Great white sharks may munch on a wider array of sea creatures throughout their lives than previously thought, according to a new study published Friday in the journal PLoS ONE.
The great whites are well known to many as the stars of "Shark Week" and as one of the ocean's most feared predators. Researchers have long believed that a shark's diet evolves over its lifetime as it grows, moving from small prey like fish to larger animals like seals and, every once in a while, humans.
But in the new study, the researchers found that great whites show a remarkable diversity in their diets. Even sharks that live near each other ate differently throughout the course of their lifetimes, and some sharks never made the transition to large animals at all.
The researchers, from UC Santa Cruz, studied the vertebrae of 15 great whites that were caught off the West Coast of the U.S. between 1957 and 2000. When sharks eat, a record of their diet is stored in their vertebrae in the form of carbon and nitrogen. Over time, the elements amass as bands in their vertebrae, akin to a tree’s rings. Because animals lower on the food chain have different levels of carbon and nitrogen in their tissue than animals higher on the food chain, researchers can tell what the sharks ate over time by looking at bands from different periods in a shark's life.