Dolphins are marine mammals that live in oceans and seas, which are salt water bodies. They have evolved to survive in salt water and have several adaptations that help them do so.
One adaptation is their ability to osmoregulate, which means they can control the balance of salt and water in their bodies. Dolphins drink salt water and then expel excess salt through their kidneys and gills. They also have special cells in their skin that help them absorb water and prevent salt loss.
Another adaptation is their thick layer of blubber, which helps them stay warm in cold salt water. Dolphins also have a rapid heart rate and metabolism, which helps them generate body heat.
Finally, dolphins have a streamlined body shape and powerful muscles that allow them to swim efficiently through salt water. They can swim at speeds of up to 20 miles per hour and can dive to depths of up to 1,000 feet.
Dolphins are well-adapted to life in salt water and are found in all oceans of the world.