The average whale shark measures about 30 feet long, with a mouth stretching nearly 5-feet across. The largest whale sharks are twice that size, stretching a staggering 60 feet from tip to tail. These gentle giants swim in tropical waters all over the world,

The world's largest great white shark is being tracked by scientists, and the predator can now be followed LIVE

The Greenland shark—the world's longest-living vertebrate—is most often associated with cold Arctic waters. However, a new international study led by researchers from the Greenland Institute of Natural Resources and the University of Copenhagen shows that Skagerrak probably serves as a nursery area for young Greenland sharks.