For a long time it was believed that the marine abysses were like immense deserts because the strong pressures to which animals are subjected impede life. In the Marianne pit (Pacific Ocean, 11, 000 meters deep), for example, each organism undergoes a hydrostatic pressure of 1064 atmospheres, that is 1064 times higher than that which we suffer on the earth's surface at sea level. But for the creatures that live in the abyss the pressure presses on every side and, like the air that weighs on us, does not disturb them. Their tissues develop in that environment, and the fluids that are found inside the body acquire such pressure that they create balance with external pressure. In these areas, due to darkness, plant life is completely missing. Food therefore "rains" from the upper layers. The organisms of the Marianne fossa are for the most part a few centimeters long: actinias, polychaetes, olotouroides (Elpidia, Myriotrochus, Scotoplanes), bivalve molluscs, isopod crustaceans, and amphipods. At smaller depths (up to 5-6 thousand meters) there is a great variety of fish: from the abyssal monkfish to the tripod fish, to pelican fish.