Having five senses at our disposal seems great, until you realise many animals have either bettered these senses or created entirely new ways of experiencing the world around them. Here are some of the special animal senses evolved over millions of years, that give them the edge over our human senses.
Our eyesight as a species is by no means poor: unlike many others, we can see in colour using three types of colour detecting receptors called cone cells. Each type of cone cell detects a different colour, which amalgamate to give us the rainbow of colours which paint our surroundings.
But that doesn’t mean ours is the best sense of sight. Our measly three cone cell types are trumped by a tiny creature sporting an incredible 15 different types of cone cell: the humble shrimp. Look around at all the colours you can see and try to imagine seeing five times as many – it’s mind-boggling!
While the visual spectrum for humans stretches from purple to red with the rest of the rainbow slotting in between, some animals have extended their visual spectrum into the ultraviolet and the infrared…
Bees can process ultraviolet light (the same light we block out with sun cream) to make the flowers they target more vivid and ensure the pollen stands out.
Caribou Spot Wolves Using UV Vision | Animal Super Senses | BBC (YouTube/BBC Earth)
This is impressive but more amazing still is that reindeer can change their perception of light dependent on the season. Santa’s helpers adapt to the scarcity of food in the winter months by stretching their visual field into the ultraviolet so that the lichen they feed on glows a striking purple against the white blanket of snow. It also helps avoid falling prey to wolves, whose coats don’t reflect UV, making them appear black against the snow in the reindeer’s eyes.
Infrared equipment like goggles and cameras help humans see in the dark by converting the heat of the surrounding environment into a coded image with the coldest areas shown in black and the hottest in white.
Certain species of snake can do this without needing specialist equipment; they simply have holes below their eyes called pit organs which house receptors that can detect heat emitted up to a metre away. This heat is mapped over the snake’s visual representation of its surroundings to create a multi-dimensional image allowing it to pin-point prey in all light levels.
Light of some sort is compulsory for vision. How, then, can some animals see in the dark? You may have noticed that nocturnal animals’ eyes shine bright in the darkness – this isn’t a trick of the light. It’s actually one of their secret adaptations for night-vision.
They reflect light back out of their eyes thus giving the light-sensitive cells in the retina of their eyes two chances to catch as many particles of light as possible which makes the world around them appear brighter.
The difference between the highest and lowest keys on a piano sound vastly different, but, as with vision, this represents just a fraction of the sound in which we are immersed. Remarkably, some animals have learnt to harness the extremes of pitch, from ultra-sound (squeaky high pitch) to infra-sound (booming low pitch).
You may recognise the word ultrasound from doctors peering into your soft tissue – or at your growing baby – but not in the context of the animal kingdom. Bats and many other species use ultrasound to echolocate, which involves firing an astoundingly high pitched noise out into the environment.
This series of high frequency sound waves reverberates off anything it contacts, such as a tasty prey item buzzing nearby. The bat then harvests the reflected sound waves and uses them to pin point the objects around them.
Dolphins are another phenomenal species which can echolocate, and have even been observed inspecting human babies hidden inside pregnant women.
In stark contrast to ultrasound, the less familiar infrasound describes sound too low in pitch for humans to hear. Infrasound fills the sea with the chorus of whales as well as dominating the land with a whole host of creatures capitalising on it including elephants, giraffes and alligators.
Low pitch sounds can travel a lot further than higher pitches, so are often used by animals occupying wide open spaces, like deserts and oceans, because they allow these animals to communicate over vast distances – thousands of miles for whale calls..
With sniffer dogs able to detect anything from drugs to cancer, we humans are under no illusions that our sense of smell leaves a lot to be desired. Some animals can smell over great distances; certain species of bear can detect smells up to 20 miles away (black bear) or through nearly a metre of ice (grizzly bear).
Other animals, such as rats, are able to accurately pin-point the source of a scent due to their ability to isolate the information from each nostril, which is being used to help detect TB, cancer and even landmines.
Star-nosed mole by US National Parks Service, Public domain, via Wikimedia Commons
But the species with the most intriguing sense of smell is the star nosed mole: these miraculous creatures can smell underwater. They do this by partially exhaling to hold an air bubble on the tip of their nose to absorb surrounding odours before inhaling the bubble and deciphering the scent molecules in it.
The sense of touch covers so much more than just feeling something make contact with the skin. In just a fraction of a second, touch receptors detect pressure, heat, texture, and even pain. The number of receptors in a given area dictate the sensitivity of this detection; in humans the areas with the most concentrated touch receptors are the lips and fingertips. Revisiting the incredible star nosed mole, their exquisite noses have six times as many sensory receptors than human hands.
All animals use taste to distinguish between the edible and the inedible, a vital function to avoid poison or over ingestion of certain compounds such as salt. But how do you decipher what is edible before it’s too late?
Catfish have devised just the tool: their bodies are covered in taste receptors so they can tell when a tasty meal is close by. This sense is crucial for survival in the murky waters they call home. In contrast, chickens come last in the pecking order – excuse the pun – with the fewest taste buds.
Here’s one us humans are completely out of our depth at sensing. Electric eels, as the name would suggest, are famous for the high voltage that surges through them, but it may surprise you to learn that other sea creatures can sense this, including sharks and lesser prey fish.
As if sharks weren’t powerful enough with their awesome jaws, lightning-fast swimming and precise sense of smell, they can also detect electricity meaning no fish is safe. Electric fields are prevalent everywhere and are distorted by movement as fine as the flexing of gills. With specialised pores filled with electro-sensitive gel, sharks can detect these changes in the electric fields to spot stealthy prey.
Super animal senses
These phenomenal ways of experiencing the world are varied and ingenious, but before we well up with envy, remember that no creature can harness the power of all of these special senses. Each species has adapted to its own ecological niche, evolving the best senses for their habitat – that is what makes the natural world so diverse and wonderful.