17 April 2012

"Starry, starry... mole?"

The star-nosed mole, Condylura cristata, is the only member of the genus Condylura and can be found in the wet lowlands of eastern Canada and in the north-eastern states of the USA, typically near to lakes, rivers and streams. The mole is small, with adults being no longer than 20cm and weighing up to a maximum of 55g; and are are instantly identifiable by the tentacle appendages protruding from their nose.

The 22 fleshy tentacles of the star-nosed mole give the species its name and are believed by some scientists to be able to detect the electrical currents emanating from their prey. However, many scientists doubt this as there is little empirical evidence to support this idea.

Unlike other species of mole, which are able to see (albeit with only limited success), star-nosed moles are completely blind. Therefore, they rely exclusively on their nose tentacles in order to detect food, such as worms, insects and crustaceans; and to navigate their way around dark tunnels and other environments. As such, their tentacles are extremely sensitive to touch stimuli and odorants and possess around 25, 000 Eimer's organs per cubic centimetre. This is much higher than in any other species of mole and their tentacles' star-shaped arrangement appears to be an adaptation that allows them to keep soil from entering their nose and to eat very small prey quickly. In fact, they are able to eat prey extremely quickly and are the fastest foragers in the animal world, taking on average of 227 milliseconds to decide whether an item is edible and to consume it. This decision making and response ability is so fast that it is at the limits of the speed of neuronal conduction!

Like other species of mole, the star-nosed mole digs shallow tunnels through the earth when foraging, which helps them to evade their predators, which include owls and hawks and to find many subterranean species of prey, such as worms. Their tunnels can be as long as 270 metres and often exit underwater, with the mole being a surprisingly good swimmer; being able to forage along the beds of rivers, lakes and streams. Interesting, star-nosed moles are also able to smell underwater, which they accomplish by breathing bubbles of air onto objects that they are interested in and then by inhaling these bubbles to carry the scents back through their nose.

Little else is known about the shy species of mole, except that it shows no preference to day, night or twilight activity (which is unusual) and remains active throughout the winter. It is also believe that star-nosed moles live in colonies, as many are frequently seen fairly close together.

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