The biggest creatures in the sea are big, but surprising new research shows they're not quite as big as we thought. Maybe that's not surprising, since it's difficult to get accurate dimensions for whale sharks, giant squid, and other "marine megafauna" because they can be hard to find and even harder to weigh and measure once you find them. (Story continues below infographic.) The research project analyzed sizes for storied sea creatures like whales and sharks and for lesser-known giants like tube worms--and the results appear in this chart. “This is the first time anyone has tried to compile anything like this and will set to rest a whole lot of myths about the size of the largest specimens of all kinds of animals,” Dr.