The mole’s 22 pink tentacles are not used for smell – but for feeling out prey (Image: Kenneth Catania)

Scientists have revealed the identity of the fastest eating mammal – the distinctly peculiar star-nosed mole.

This mole finds, identifies and wolfs down its food in an average of just 227 milliseconds – less than quarter of a second. By comparison, it takes people 650 milliseconds to brake after seeing a traffic light turn red.

“I don’t know of any other mammal that comes close to this,” says Kenneth Catania, a biologist at Vanderbilt University, Tennessee, US, and lead author of the new study.

The key to the mole’s speed feasting is its odd snout, which looks like an anemone with 22 pink tentacles. But the tentacles are not used for smell – instead the mole uses them to feel around in the darkness for potential prey.

Using a high-speed video camera, Catania and his colleague Fiona Remple found that when a tentacle touched something, the mole made very quick decisions about whether that object was food or not, usually in about 8 milliseconds.

Data processing

The pace of the star-nosed mole’s feeding is so fast that it is approaching the maximum speed at which its nervous system can process information.

In fact occasionally it does outpace its own brain and skips over objects that were food. Once its brain catches up and realises that the morsel was edible, the mole does a double take and returns to the food.

In the natural world, it is rarely cost efficient to pursue small prey because the energy expended is greater than that provided by the food.

However, as the time taken to retrieve small prey falls, it becomes more and more profitable in terms of calories consumed. The mole’s quickest time from touch to eat was just 140 milliseconds.

Bountiful buffet

Catania was not certain what the moles ate in their natural habitat in Canada and north east US, but the marshes in these regions provide a bountiful buffet of small invertebrates. In the lab, Catania fed the moles 1 to 2 millimetre bits of earthworms.

The mole’s star-shaped nose is not its only adaptation helping it to feed at speed. Its unusual tweezer-shaped teeth also aid in its specialised dining by grabbing small prey more easily.

And the mole’s brains have adapted to speed eating too. Most species of mole have two areas in the cortex devoted to touch, but the star-nosed mole has three.

“This is an example of the extremes to which predators may be pushed to achieve a diet that will supply them with the nutrients that they need,” Catania told New Scientist.

Journal reference: Nature (vol 433, p 519)