Weird Animals - the Star-Nosed Mole

The star-nosed mole (Condylura cristata) is a small, weird-looking semi-aquatic mammal that is found in the wetlands of eastern North America ranging from Canada to Georgia. It lives in narrow underground tunnels and feeds on larva, insects, worms, crustaceans and molluscs. Because it lives in almost complete darkness, this mole is virtually blind.. So it relies mainly on its remarkable-looking star-shaped nose to locate food. Yes, that’s the mole’s nose you see in the photos, not its back end.

Let me tell you about the star-nosed mole’s most distinctive feature – you guessed it – its remarkable nose. There is a circle of 22 mobile, pink, fleshy, finger-like tentacles at the end of its snout which looks like a star, or more precisely, like a rosy, hot-pink lampshade with tassels. These incredibly sensitive nasal tentacles are covered with approximately 25,000 tiny touch receptors known as Eimer’s organs, which are used to identify food. The receptors got their name from Theodor Eimer, a German zoologist who first described these incredible tentacles in 1871.

This unique-looking mammal is covered in thick black-brown water-repellent fur, has large scaled hands with what look like over-sized fingers, and a long, thick tail, which functions as a fat storage reserve. Adults are 6 to 8 1/4 inches in length, weigh 1 to 2 5/8 ounces, and have 44 teeth. Its teeth are almost as strange as its nose. The incisors are very small compared to other moles and are formed like tweezers. This allows them to grasp small prey very precisely. When the mole is foraging, presumably for earthworms, its favorite food, its tentacles are constantly in motion. When it eats, however, they are clumped together out of the way.

Star-nosed moles have small, beady eyes but extremely poor eyesight. (Which may be a good thing, or how would they ever find a mate)? So they continually survey their environment by repeatedly touching the objects around them with their star-nose appendages. Researchers who timed the moles' activities found that after touching a small piece of food they took an average of 230 milliseconds to identify it as edible and eat it. That’s milliseconds, folks, thousandths of a second. A report in the journal, Nature, gives this peculiar mole the title of fastest-eating mammal.

When the outer appendages or tentacles of its nose come into contact with potential food, the mole moves its nose so that the two lower tendrils which are the most sensitive can identify the prey. The mole can touch 13 separate areas of the ground every second, and can locate and consume 8 separate prey items in under 2 seconds. Once its dinner of “fast food” has been identified, it is captured with its tweezer-like teeth.

The nose that smells.     

This mole is a good swimmer and although it digs shallow surface tunnels for foraging, often these tunnels exit under water. Its remarkable nose also possesses the ability to identify smells under water. How? It exhales air bubbles on to objects or scent trails and then inhales the bubbles to carry the smell back through its nose. This enables the star-nosed creature to decide whether something is edible with incredible speed. The Guinness Book of Records identifies this amazing mole as the world’s fastest forager, and also with the ability to “sniff out” food under water.

With a face like theirs, these moles might seem to be in danger of scaring away all their food. But these bizarre-looking creatures can detect a snack and gulp it down all under a quarter of a second. As fast as some species of fish.

The latest research reveals that the mole’s star-nose is a tactile organ more than six times as super-sensitive as a human hand, but it also has something in common with eyes. Scientists are comparing the waving of the star-nose-tentacles to the visual tracking of an animal eyeball. In other words, this is a nose that not only feels and smells but sees.

Humans, like most animals that rely primarily on sight, continually shift their eyes. When an interesting or important image enters our peripheral vision, we instinctively shift our eyes to move the image into the central part of the retina (fovea).

Similarly, star-nosed moles continually wave their nose tentacles around. When something of potential interest is detected, such as an unfortunate earthworm, then the mole moves its nose quickly to bring one of the central tendrils into contact, giving it a superior tactile image of the object so it can determine whether it is something good to eat. For small prey the entire process from first touch to complete ingestion takes about a fifth of a second.

Addenda. Adept at burrowing on land, the star-nose mole is also a powerful swimmer and spends much of its time behaving like a fish. It propels itself in water, even under ice, by moving its feet and tail in unison. It is more dependent on water during winter, when the frozen ground makes obtaining its usual foods difficult. While swimming, the mole blocks its nostrils with its multi-tasking star-nose.

The star-nosed mole mates in late winter or early spring, and the female has one litter of 4 or 5 young in late spring or early summer. At birth, each offspring is hairless and weighs less than ½ ounce. Their eyes, ears, and star are all sealed, only opening and becoming useful approximately 14 days after birth. The young develop rapidly and leave the nest to hunt for themselves after three to four weeks. They are fully mature after 10 months. Predators they must avoid include the red-tailed hawk, great horned owl, skunks, and even large fish.

One more anomalous fact: unlike the rest of the animal kingdom which follow a logical outward or sprouting strategy when it comes to growing limbs, the star-nosed mole’s 22 tentacles do not extend or poke out from its face at birth but take a reverse approach. The moles are born with a swollen nose ridge that eventually comes loose at the back, extruding the stringy nose-tendrils contained within so that they spring out and curl forward.

The star-nosed mole may be weird and more funny-looking than any other . . . . But it’s amazing and astonishing, and beautiful – to its mother.

© Copyright BJ Rakow 2010, 2012. All rights reserved.

B. J. Rakow, Ph.D., Author, "Much of What You Know about Job Search Just Ain't So." This serious and comprehensive job search book is written in a light-hearted fashion.