Star-nosed moles don't just look bizarre, they are bizarre.
Of course, bizarre here means “weird but amazing”. 25 years' worth of research has gone into the discovery of the star-nosed mole's evolution, physiology, and behavior. Kenneth Catania, a biologist and neuroscientist considered to be the world's leading expert on the star-nosed mole, has uncovered a number of fascinating things about the strange creatures over the years.
These discoveries can also benefit humans. For example, understanding the mole's sensitive star-shaped nose can provide insight into how touch works at the molecular level. This can lead to the development of new treatments for pain.
So what bizarre and surprising things can these moles do?
There are only two known animals whose sense of smell still works even when they're underwater. One is the American water shrew, while the other is the star-nosed mole. A star-nosed mole would blow bubbles into the water, then inhale the bubbles back so they can detect the smell of prey.
Catania discovered this ability by training moles to follow a scent trail underwater. This trail will lead the moles to food. Catania set up a steel grid that covered the scent trails and blocked the moles' noses. Bubbles, however, can pass through the grid. The moles were able to trace the scent back to food with an 85% accuracy.
These moles take almost no time at all to decide whether or not to eat something and to consume it entirely. Once their noses touch something, they need only eight milliseconds to determine if the object is edible. Within a quarter of a second, the food would be gone. Sometimes, the mole's eating speed even outpaces its own senses, thereby making the mole skip over something edible. When its nervous system finally catches up, the mole would go back to the morsels it missed.
There are a whopping 100,000 nerves fibers in the star-nosed mole's nose. This is five times the number of nerve fibers in the human hand. Imagine all those nerve fibers in a spot smaller than a fingertip.
Star-nosed moles have such sensitive noses that Catania has not yet determined “the lowest threshold for activating neurons”. He claims that understanding the moles' sense of touch can help scientists better understand human sense of touch.
These extremely sensitive noses also help the moles, which are almost blind, seek out their prey.
The touch fovea, a small area at the center of the mole's nose, essentially functions as the mole's eyes. The neurological organization of the touch fovea is similar to that of a complex visual system.
Think of the way you're reading this text. Your eyes shift as you read one word after another. The mole works in the same way. It shifts its fovea from one point of interest to another.
This parallel indicates that high-resolution sensory systems have common strategies of development.
When scientists want to map out human brains, or those of other animals, it can be a complicated process. That's not the case with star-nosed moles. Catania used cellular stains to determine how the moles' brain processes stimuli. The stains revealed a star-shape in the moles' neocortex. Catania was able to produce a representation of the right side of the moles' nose in the left hemisphere of their brains. The use of cellular stains made it possible to make measurements that would otherwise be difficult to make in other animals.
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