Ocean researchers recently solved a great mystery about some of the world’s most feared and fascinating animals. Great white sharks star in Hollywood movies, get in-depth Discovery Channel coverage for an entire week each year and haunt beaches and vacations all summer long. And even though these great fish of the sea have existed since the time of the dinosaurs, there is still much that we don’t understand about the great white shark.
Where Do Great Whites Go For The Winter?
One thing we didn’t know about the great whites that frequent California in the summer was where they go once winter rolls around. Some scientists figured out how to lo-jack some great whites and followed them to what looked like a vast void in the middle of the Pacific. This migration spot puzzled researchers who saw it as a dead zone. Great white sharks like to eat seals. That is why they show up at popular swimming areas along the California coast and vacation spots on the Atlantic, such as Cape Cod in Massachusetts.
Seals are mammals, but unlike whales—the largest sea air-breathers—they like to be near land. Out in the middle of the sea, there are no seals. This fact led to much speculation about the shark’s destination. But when ocean scientists looked at this vast 160-mile radius area between California and Hawaii, they noticed it was actually chock-full of tasty tidbits.
Welcome to “White Shark Cafe”
Rather than a cold and empty void, this region has a rich mid-water area that is well-stocked with squid and small fish. The sharks weren’t swimming away to some spot to rest up for the winter, they were going to a veritable smorgasbord.
So, how did the scientists pinpoint where these sharks fled? Through advances in technology, researchers were able to tag certain sharks during their summer frolicking. These pinger tags emit a radio-frequency-signal that allowed the researchers to follow their every move. In addition, the tags also were programmed to detach and float to the surface when the sharks reached their winter feeding spot.
The Cafe Is Wide And Deep
And while the feeding grounds are known to cover a surface region of the Pacific that is roughly the size of Colorado, the surfae area is nothing compared to its volume. Once tagged and monitored, scientists learned that the great sharks were diving deeper than ever thought possible. Here the great white’s food runs reached depths of up to 3,000 feet. These depths are cold and inhospitable to the sharks, but sometimes a warm current flows to these depths. When this happens, schools of squid and fish dive, and the sharks follow.
The sharks follow a diving pattern. During the day, sunlight allows them to dive deep, while at night, they restrain themselves to a shallow dive. The researchers also noted that as summer approaches, male and female sharks approach hunting differently. The males begin rapid repeated diving—up to 140 times a day—while the females continue a night/day pattern.
The reason for this gender difference is now a new mystery for the scientists to ponder.
