Dr Michelle Dickinson: nanotechnologist on the new research revealing wrinkles can determine whether an elephant is right or left-trunked

The Sunday Session with Francesca Rudkin

The next time you head to the zoo and see an elephant, look closely at its trunk, you might be able to tell if it's a "lefty" or a "righty" based on its whiskers and wrinkles.

A study published in the journal Royal Society Open Science offers a clever way to identify an elephant’s preferred "handedness" by examining the wrinkles and whiskers on its trunk. Just as humans tend to favour one hand, elephants often prefer to bend their trunks either to the left or right when grabbing objects like fruit. This preference, known as "trunkedness," leaves two tell-tale signs:

1 - Whiskers on the side opposite the curl become shorter and sparser from constant contact with the ground.

2 - The skin on the curled-in side develops more wrinkles over time.

The study closely analysed the skin wrinkles formed on the trunks of both living and deceased zoo elephants. They found that trunk wrinkles start forming in utero and double about every 20 days during an early phase of rapid development. Like humans, elephants accumulate more wrinkles as they age. For example, new-born elephants have an average of 87 wrinkles, while older elephants sport around 109.

Elephant trunks are extraordinary, and attract the attention of researchers in fields like soft robotics as trunks function as muscular hydrostats - meaning they have no bones, but are made up of an intricate network of 46,00 muscles. In comparison, the human body has just 600 to 700 muscles.

While a trunk’s flexibility is remarkable, its thick outer skin also plays a crucial role. Surprisingly, this skin on the trunk of an elephant is stretchier on the upper surface than on the underside, which allows for the delicate manoeuvres elephants are known for, like peeling a banana or picking up a tortilla chip without breaking it.

But these wrinkles are more than just signs of aging - they are essential to an elephant’s survival. They help protect the flexible trunk and aid in gripping heavy objects. The combination of flexibility, strength, and unique skin characteristics makes the elephant trunk highly unique in nature and a source of valuable insight for robotics and other fields.

LISTEN ABOVE

See omnystudio.com/listener for privacy information.