Videos of animals getting spooked minutes before an earthquake hits and tales of man’s best friend sniffing out cancer in their owner’s hint at a world beyond what humans can sense. There is evidence showing that some animals not only possess enhanced sight, hearing, taste buds and greater sense of smell and touch, but also further senses which detect things we humans have no natural perception of.
Perhaps the most interesting and super hero-like of these is the ability of sharks and rays to detect the electrical currents generated by fish and other prey. Salt water acts as a magnifier for the natural electricity generated by living things and receptors called ampullae de Lorenzini, located on their top lip, allow sharks to detect this electricity. These electroreceptors kick in when the shark goes for the killing stroke. It guides the shark as its eyes are rolled back for protection, leaving it momentarily blind. On land, a group of animals called monotremes – egg laying mammals which include platypus and echidnas – also use electroreception to find insect prey with their highly sensitive snouts.
There is also some evidence that these electroreceptors can aid in navigation which tends to be the focus of many of these strange extra senses. Magnetoreception (detection of the Earth’s magnetic poles) is a commonly known extra sense which has progressed from a ridiculed idea to well-accepted over a generation. Turtles, bird and bees have all been experimentally shown to possess internal compasses which presumably help with migration and other feats of navigation. There are also some stranger manifestations of this navigation sense, such as the tendency of cows to orient themselves to a certain magnetic field line. Both the occurrence and function of this is hotly debated, though.
There is even a recent study hinting at human’s magnetoreception abilities which involved seating the participant in a chair facing north and changing the orientation of the magnetic field in the room. When the magnetic field is flipped so magnetic north in the room was the opposite to normal, the study found that there was a drop in alpha waves in the brain signifying that information processing was occurring. This suggests that the change of the magnetic field was detected by the body. Nonetheless, whether humans in fact register and act on this information is far from being proved.
However, there are some humans genuinely born with super senses. The average human possesses three cones in their eyes which allow us to see visible light. About 12% of women are born with a fourth cone and this condition, called tetrachromacy, allows them to detect more differences between colours than the average person. This is not easily diagnosed as the colour differences cannot be displayed on a screen, though women with this ability see a more vibrant world than us. Animals still trump humans in the sense that the fourth cone found in birds, some fish and reptiles allow them to see ultraviolet light. This is thought to change the perception of colours in birds and affects mate choice in colourful and drab species alike.
Science may not yet be able to answer the old philosophical question of whether the person next to you sees colours in the same way as you, but it is allowing us to gain an insight into how others see the world – and it turns out humans are oblivious to much of it.
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