Sharks such as the mako shark are perfect swimming machines, capable of speeds of up to 75 kph. Their sleek shape means they can move quickly through the water and turn at speed.
Is it true? Sharks never have a break.
No. Sharks living near the surface must swim all their lives to avoid sinking. But other like nurse shark spends most of their time motionless on the seabed. Nurse sharks can pump water over their gills and so they don’t need to keep moving.
Why are sharks darker on top?
Sharks that swim near the surface are dark on top and paler on their undersides. This means they are difficult to see from above or below as they hunt for prey.
Amazing! Most sharks drown if they stop swimming, as no oxygen-rich water is passing over their gills. They also sink. They do not have a swim bladder like other fish. They have a huge oily liver instead, which helps to keep them afloat.
How do sharks breathe?
Like all fish, sharks extract oxygen from the water using their gills. Water enters their mouths, and oxygen is absorbed as the water passes over the red, feathery, blood-filled gills. Most sharks keep moving all the time in order to get a constant supply of oxygen.
Picture Credit : Google