The ocean has an average depth of approximately 3.7 kilometres (or 2.3 miles). A calculation from satellite measurements in 2010 put the average depth at 3,682 metres (12,080 feet). However, at the ...

allowing it to detect faint light from above while remaining hidden. The dragonfish, another deep-sea marvel, combines its glowing features and translucent teeth for camouflage and communication ...