PARIS - An elephant's trunk can surpass a human's height and lift trees -- a marvel of strength that's conversely so gentle it can grasp a tortilla chip without breaking it.
So how do the thick-skinned animals with poor eyesight pull off such delicate tasks? In a word, whiskers.
New research published in the journal Science details how the whiskers that cover an elephant's trunk have unique properties that lend the largest land mammals remarkable dexterity.
Elephants are born with about 1,000 of these bristles, lead author Andrew Schulz told AFP, many of them anchored in the trunk's wrinkles to act like feelers and help the animals assess their surroundings.
A team of engineers, materials scientists and neuroscientists analysed the geometry, porosity and material properties of these whiskers, and expected them to mimic the whiskers found on mice or rats -- circular at a cross-section, solid and uniformly stiff.
In fact, elephant whiskers are almost blade-like, with a porous architecture similar to sheep horns, which helps with shock absorption while eating.
And a graduated shape and structure from base to tip allows for an amplified sense of touch, Schulz said.
"The craziest finding that we had, I think, was that these whiskers have this transition from a really, really rigid base to a very, very soft tip," said the researcher at the Max Planck Institute for Intelligent Systems in Stuttgart, Germany.
Part of elephants' whisker evolution is to prevent breakage, said Schulz. Unlike most mammals with whiskers, those of elephants don't grow back.
Many animals have sensory hairs that can act as a radar, but few quite so precise as the elephant's.
Schulz said a rat's whiskers, for example, also picks up vibrations -- but it's akin to smashing down a handful of keys on a piano.
To an elephant's whiskers, it's more like hitting specific notes.
Researchers voiced excitement that cat whiskers have a similar kind of material intelligence and stiffness gradient.
Elephants are also well-documented using their trunks for social touch -- "they're using the outside of their trunk," Schulz said, "so they're using those portions that are covered in the whiskers."