^w^ Since sharks do not have air bladders, their depth range is not restricted the way it is in bony fish, which do have air bladders.
^w^ The liver, the largest organ in the shark's body, is filled with a very low density oil that is lighter than water and acts as an internal life preserver.
^w^ The oil reserve does not make a shark neutrally buoyant, but it does allow it to maintain position while exerting minimal energy.
^w^ Unlike other animals, all the fatty reserves in the shark's body are stored in the liver, giving the liver an energy storage function.
^w^ The liver can occupy up to 90% of the shark's body cavity but accounts for only 25% of its weight.
