Elephants' Trunks Are Like Super-Strong Gumby Arms

AUSTIN, Texas — The marvel that is the elephant's trunk — an extendable nose that can also help the pachyderm eat cereal and even paint — has just outdone itself. Researchers have found this impressive sensory organ can telescope out 25% farther than its length at rest by unstacking its wrinkles of skin.

Until now, no one had measured how far an elephant could stretch its trunk — at least not in a scientific capacity, said Andrew Schulz, a conservation physicist at Georgia Institute of Technology, and lead author on the study presented here at the Society for Integrative and Comparative Biology meeting on Sunday (Jan. 5). 

Schulz and his colleagues worked with one of the African elephants at Zoo Atlanta, a 9-foot-tall (2.7 meters) adult female named Kelly, to figure out the answer. The team recorded video of Kelly stretching her long nose out as far as she could to reach a treat held up by her keeper at varying distances.

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They found that Kelly could extend her trunk by 25% of its collapsed, or resting length. To give you an idea of just how significant that change is, it's about the same as the difference between the height of actor Kevin Hart, who is 5 foot 4 inches (1.6 m), and that of professional basketball player LeBron James, who's 6 feet 9 inches (2.1 m).

The researchers said that figuring out how far an elephant can stretch its trunk will be helpful for conservationists looking to develop effective ways to mitigate human-elephant conflict. "People don't know what the elephant's capability is," Schulz said, which means efforts to protect themselves from elephants could be in vain. 

For example, when constructing a fence to protect crops from being eaten by elephants, farmers in Africa will factor in the length of an elephant's trunk at rest, but not how far it could stretch, Schulz said. So, if an elephant is enticed by a yummy row of crops on the other side of that fence, the clever animal could stretch out its trunk to reach its target snack and still do damage because the fence wasn't placed at the distance of a stretched-out trunk. 

As Kelly stretched her trunk, the wrinkled skin on her trunk unstacked in sequence, similar to extending a telescope. "So, you see it first extends the tip, and you can see it kind of travels like a wave along the trunk," Schulz said, but it doesn't stretch out uniformly. "The midsection doesn't have as much stretchiness as the tip and the base, and we have no idea why." Schulz and his colleagues hope to unravel that mystery by taking a look inside an elephant's trunk. 

The finding has robotics applications, too. Figuring out how to make a robot that has both traits, like elephants do, could improve rescue operations in situations where people are trapped below ground or under a large amount of rubble, such as in a mine or collapsed building, he said. 

"Elephants are really, really smart," Schulz said, but they haven't let us humans in on the secret of their super-strong, super-flexible trunks. 

Originally published on Live Science.

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Kimberly Hickok
Live Science Contributor

Kimberly has a bachelor's degree in marine biology from Texas A&M University, a master's degree in biology from Southeastern Louisiana University and a graduate certificate in science communication from the University of California, Santa Cruz. She is a former reference editor for Live Science and Space.com. Her work has appeared in Inside Science, News from Science, the San Jose Mercury and others. Her favorite stories include those about animals and obscurities. A Texas native, Kim now lives in a California redwood forest.