The Star-Nosed Mole Is Almost Too Weird
The more we learn about the star-nosed mole, the stranger this animal gets—and that’s saying something. We learned just a little bit more this week, as mole expert Kenneth Catania presented his latest findings at the 2017 Experimental Biology Meeting in Chicago.
The neuroscientist has been obsessed with the lumpy, hamster-sized creatures since his days as a research assistant at the National Zoo.
“Obviously they are among the weirdest looking creatures on the planet,” he said in a statement. "But when I began trying to understand the star, the mole’s brain organization, and its behavior—that’s when things got really surprising.”
In 2011, for example, Catania realized that the moles have developed a technique for smelling underwater. They aim their strange snoots at fish or other prey, then start blowing bubbles. The bubbles bounce off the hapless prey and are instantly snorted back up by the mole, who reads the scent of the captured air.
The mole’s “star” is an extraordinary organ unlike anything else in the animal kingdom. It’s a cluster of prehensile tentacles packed with more than 100,000 sensory receptors. (A human fingertip, one of the most sensitive parts of our body, has about 3000.)
The star's receptors are unbelievably responsive, Catania said—“so sensitive that we have not been able to determine the lowest threshold for activating neurons.”
This super sensitivity gives blind moles a huge advantage over their prey. It only takes 8 thousandths of a second for them to identify something they’ve touched, which means they can spot and gobble up a juicy worm before the worm even realizes what’s happening. No mammal eats faster.
The root of the star’s dazzling capacity is a tiny section called the touch fovea, which functions almost exactly like our eyes. As the mole turns its attention to an object, the touch fovea moves over it and focuses, as your gaze might rest and zoom in on a plate of cookies.
"These parallels suggest there are common strategies by which evolution 'builds' high-resolution sensory systems,” Catania said, “whether they are based on sight or on touch.”
Weird? You bet. But to those like Catania who know them best, they’re "truly amazing animals.”