From 1,000m down to around 4,000m (13,123 ft). By this depth the ocean is almost entirely dark (with only the occasional bioluminescent organism, such as lanternfish). There are no living plants, and most animals survive by consuming the snow of detritus falling from the zones above, or (like the marine hatchet fish) by preying upon others. Giant squid (as well as smaller squids and dumbo octopi) live at this depth, and here they are hunted by deep-diving sperm whales. From Greek βαθύς (baths), deep.