Sharks and dolphins are alike in many ways, sharing several physical characteristics such as their side fins, dorsal fins and torpedo-shaped bodies. Although these animals vary wildly – one is cold-blooded and one is warm-blooded – they both evolved for underwater speed.
Sharks, which evolved several million years before dolphins, first adapted to the water with their hydrodynamic bodies. Dolphins, which evolved long after sharks from land mammals, adapted to the water with similar physical characteristics.
The coloring of both sharks and dolphins acts as camouflage. Their backs are a dark gray or blue, and their bellies are a light gray or white. This helps them to blend into the ocean when seen from above and below.
However, there are many difference between dolphins and sharks as well. For instance, dolphins are warm-blooded mammals, while sharks are cold-blooded fish. Dolphins have thick, rubbery skin and a layer of blubber that insulates them from the cold. Sharks have scales that aid in their movement. Sharks don't blink, and the water provides lubrication for their eyes. They do have a protective membrane that covers their eyes when in danger. On the other hand, dolphins secrete a mucus that lubricates their eyes and protects them from infection.