A jellyfish is 95% water, a dog is 70% water and a frog is 78% water.

The youngest swimmers to cross English Channel were a girl and a boy, both aged 12.

Water for the transport of animals

Water makes up almost half of the volume of human blood. A person has about five liters (10.5 pints) of blood, which is made up of two main parts, plasma and cells. The plasma is a sticky, straw-colored liquid made up mostly of water. There are many substances dissolved in the water. Food materials, such as glucose, and amino acids are absorbed from the intestines and carried by the blood around the body to the individual cells. The blood also picks up waste material, such as urea. This diffuses from the cells and dissolves in the water of the plasma. The urea is carried by the blood to the kidneys where it is removed. Another waste product, carbon dioxide, is carried by the blood from the cells to the lungs. Special chemical messengers, called hormones, are also carried in the blood. Hormones have very specific roles in the body. For example, the hormone adrenaline prepares the body for either "fight or flight." If you are frightened, it is released from a tiny gland near the kidney and carried to the organs of the body by the blood. It causes your heart to beat more quickly and makes you breathe more rapidly.

There are three types of cell suspended within the plasma: red blood cells, white blood cells and platelets. The red blood cells are responsible for transporting oxygen. They pick up oxygen in the lungs and carry it to every cell in the body. The white blood cells play an important role in the body's immune system. They destroy bacteria and other disease-causing organisms that gain entry to our bodies. The third type of cell, the platelets, are tiny fragments of cells. Their job is to help the blood to clot when a blood vessel is damaged.

Animals living in salt water

Animals that live in salt water have that contain a weaker salt solution than the surrounding sea. Due to the natural process of osmosis, water would want to leave their cells .If too much water left their bodies; they would dehydrate and eventually die. They also face another problem connected with the salt water .If they drink the sea water, they would consume a lot of salts that their bodies do not need and that could be damaging to them.

Many marine organisms survive in the sea by altering the salt concentration of the fluid in their cells so that it is exactly the same concentration as the surrounding water. This means that there will be no gain or loss of water. Some marine creatures remove unwanted salts from their body by pumping them out through a special adapted gland.

Desert adaptions of animals

Animals also need water to survive, so those that live in deserts have to be specially adapted to conserve water. The camel saves water by not sweating and by allowing its body temperature to rise. The kangaroo rat never needs to drink water since it gains all the water it needs from its food. Water is released as food substances are respired, or broken down, within each cell. This water, called metabolic water, is just sufficient to enable the kangaroo rat to survive. Desert predators, such as the fennec fox and the jackal, obtain the water they require from the bodies of the animals they kill and eat.