In our familiar world, the power of comprehensive sight is only possible as the sun illuminates our environment. However, the aquatic world can be highly variable. For example, some of the rivers in western and central Africa can contain such a high quantity of suspended matter that vision is all but impossible. One particular fish (and its close relatives) has devised a unique method of navigating their environment and seeking food items. The elephantnose fish (Gnathonemus petersii) uses its specialised muscle-derived cells to emit short, low-powered pulses of electricity into the water whilst using electroreceptors covering its skin to listen to the returning electrical echoes. This allows the fish to determine the location of objects and prey items, in a similar way that bats use sound for echolocation. This system is so accurate, some researchers have hypothesised that it is as efficient as the power of sight. However, all this complex processing does come at a cost – compared to other animals, elephantnose fish spend 60% of their oxygen intake on their brains to process all this data – compared to us humans where only 20% oxygen intake is used by our brains!
Tagged in: Aquatic Adaptations