With noses that touch instead of smell, and eyes that don’t see, star-nosed moles are fascinating creatures. They eat at record-breaking speeds and are one of only two mammals that can “smell” underwater.
Writer: Priya Ord
Editor: Maria Stoica
Artist: Suzie Mishima
Picture a mole. Picture a 22-sided star. Picture a mole whose nose is a 22-sided star and you’ve got yourself a star-nosed mole!
Star-nosed moles (Condylura cristata), native to the wet lowlands of eastern North America, are peculiar-looking animals. These moles show extreme evolutionary adaptations and it is thought that their star-shaped nose evolved to aid hunting in the competitive wetland environment.
Funnily enough, they don’t actually use their nose to smell–instead, they use it for touch.
Their nose is the most sensitive touch organ known in any mammal–approximately 30,000 sensory Eimers’ Organs cover their 22 fleshy appendages.
Star-nosed moles use their nose the way we use our eyes to understand the environment. Research suggests that their brain is organised to receive signals from their noses, similar to how human brains are arranged by visual information from the eyes.
They spend much of their time burrowing underground, using their front legs to dig; thus, they are functionally blind. To hunt, they touch their nose against the soil at a rate of 10 or 12 touches per second. Each touch sends sensory information through 100,000 nerve fibres to the brain. Their nose contains five times more touch sensors than a human hand, despite the diameter of the star being smaller than that of an average human fingertip. Dr Ken Catania, Stevenson Professor of Biological Sciences at Vanderbilt University, said, “Star-nosed moles have extremely efficient nervous systems that convey information from the environment to their brains at speeds approaching the physiological limits of neurons.”
Carnivorous star-nosed moles are the fastest-eating mammals on Earth; in less than a quarter of a second they can locate, identify and eat their prey. They take 200 milliseconds to identify the prey and only eight milliseconds to determine if it is edible.
They are semi-aquatic and one of few mammals (alongside the water shrew and Russian desman) that can “smell” underwater. They achieve this by blowing bubbles (5-10 small air bubbles per second) towards an object or a scent trail and then quickly re-inhaling the odour molecule-containing bubbles to retrieve the scent.
Star-nosed moles are curious-looking creatures – but there is much more to them than their uncanny looks!