Blue Marlin
Blue marlins are among the largest, fastest, and most recognizable fish in the world. Their cobalt blue and silvery white bodies and spear-shaped upper jaws make this big fish stand out in a big ocean.
Just how big is a blue marlin? Female blue marlins can grow up to 14 feet (4.3 meters) in length and can weigh more than 1,985 pounds (900 kilograms)!
This incredible predator lives a solitary life from the time it is born. The mother lays her eggs in the open water and they float along until hatching with no parental care. From then on, the fish spends most of its life alone, far from land, in the warm surface waters of the Atlantic, Pacific, and Indian Ocean.
Blue marlins usually feed at the surface where the water is warm, but they have been known to dive deep to feast on squid. To catch prey, blue marlins swim through dense schools of mackerel and tuna at full speed, slashing their upper jaw. They go back to the school to eat their stunned victims.
Bottlenose Dolphin
Bottlenose dolphins send messages to one another in different ways. They squeak and whistle and use body language—leaping as high as 20 feet (6 meters) in the air, snapping their jaws, slapping their tails on the surface of the water, and even butting heads. Dolphins also produce high frequency clicks, which act as a sonar system called echolocation (ek-oh-low-KAY-shun). When the clicking sounds hit an object in the water, like a fish or rock, they bounce off and come back to the dolphin as echoes. Echolocation tells the dolphins the shape, size, speed, distance, and location of
the object. Bottlenose dolphins
also have a sharp sense of hearing.
Scientists believe that the sounds
travel through the dolphin's
lower jaw to its inner ear
and then are transmitted to the
brain for analysis.