The nosiest of moles
The star-nosed mole (Condylura cristata) is a champion feeler. Native to eastern North America, these hamster-sized creatures do have eyes but they are much reduced so they are effectively blind. Instead, the moles rely on their uniquely weird star noses to find their way around.
Star-nosed moles live in underground (sometimes underwater) tunnels in wetland areas. They eat small invertebrates, aquatic insects and even small amphibians and fish. Their noses are key tools for finding their dinners.
We use our senses to discover the world. As humans, we usually rely on eyesight while the other senses kick in to fill the gaps. Yet many animals don’t live in a visually-dominated world. Some creatures feel instead of see the world around them, and they don’t just use their hands.
The moles’ noses are made of 22 separate appendages that resemble small wormy protrusions (sometimes described as looking like sneezed-up intestines!) Each appendage is covered in thousands of tiny, highly sensitive Eimer’s organs which allow the animals to gather information about their environments at super-fast speeds.
The moles use their wormy noses to feel their way to a tasty dinner. The sensitive organs on each appendage provide a rapid response touch system that detects potential prey in the moles’ dark, underground world. Incredibly, star-nosed moles can detect and identify a prey item, move it to their mouth, consume it and start looking for more food in just 0.12 seconds: five times faster than the speediest of humans. This unique ability has placed star-nosed moles in the Guinness Book of Records as the fastest forager in the animal kingdom. Even though each item of food may not be very nutritious, the short food handling time allows star-nosed moles to gain the maximum benefits in the shortest possible time.
The sensitive noses also come in handy underwater. Most land animals cannot use their sense of smell underwater because we need air to transport the smelly molecules. Star-nosed moles often forage underwater and, with their poor eyesight, they need a way to find their food. The solution: become a bubble sniffer! Kenneth Catania from Vanderbilt University in Tennessee used high speed video photography to figure out how star-nosed moles sniff underwater. He discovered that the moles blow lots of small bubbles while they’re swimming and then quickly sniff them back up into their nose. If the bubbles encounter something smelly, then that scent will reach the moles when they sniff the air bubbles back up again.
Other species of mole also have sensitive Eimer’s organs but they have not developed the tentacle-like nose appendages. The reason may lie in the star-nosed moles’ habitat. They live in wetland areas and generally consume soft-bodied insects. This environment is far less abrasive than the drier soils that other mole species inhabit so perhaps the moist environment allowed the starry appendages to evolve.
Whether it’s high-speed prey detection or sniffing underwater, it’s clear that star-nosed moles are truly weird and wonderful creatures.
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