We cannot even grasp all of the creatures living deep in the ocean and the sea. There are just so many species living underwater.
The term deep sea creatures refers mostly to organisms that live below the photic zone of the ocean. They are used to surviving in extremely harsh conditions. For example, they can survive hundreds of bars of pressure, but also small amounts of oxygen, no sunlight, and limited sources of food.
These creatures depend on food floating down from above. The water deep in the sea reaches temperature between 3 and 10 degrees Celsius, and has very low oxygen levels.
How do these creatures survive? This documentary takes a look at how the deep sea creatures adapt so they can survive the harsh environment.