Saltwater fish have to drink water. The saltwater draws out their fluids therefore they have to replenish it. Fresh water fish get their water through osmosis. They have tiny holes in their skin that draws in the water.

A dolphin only half sleeps. Its brain is divided into two hemispheres. One side, the left side sleeps while the other side, the right side, stays awake. After eight hours the right side will sleep and the left side will stay awake. This allows the dolphin to be alert enough to avoid any danger.

By: Bertha Sutliff