Squalene is an oil which is derived from both plant and animal sources. Small amounts of squalene are produced by the human body and can also found in many vegetable oils. Much larger quantities of squalene can be derived from certain fish oils. The most common and valuable source of squalene is found in the livers of deep-sea sharks. Squalene is a low-density compound often stored in the bodies of cartilaginous fish, such as sharks, which lack a swim bladder and therefore must reduce their body density with oils and fats. Squalene is mainly stored in the sharks liver. Deep-sea sharks have a unique ability to survive in water of depths between 600m to 1000m. The secret to their survival in such extreme conditions with poor oxygen and high pressure is their liver. A sharks liver can account for 25 to 30% of its total body weight.