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To live with an elephant trunk would be a rich life indeed, and recent research from the Georgia Institute of Technology has only deepened the envy that we as a species should feel over this multifaceted appendage. Published in the Journal of the Royal Society Interface, the study found that the nostrils of an elephant’s trunk can dilate in order to store as much as 9 liters of water, handy for an animal that gets through two bathtubs' worth of water a day. On top of this, they can suck water up at unfathomable speeds, roughly 30 times that of a human sneeze. Evolution really did us dirty.
The manipulation of liquid, gas, and solids across the animal kingdom is an endless resource for human innovation, inspiring technologies used in healthcare and at home (did you know some handy suction devices were inspired by remoras?) The researchers were particularly interested in elephants and their trunks because they are unique in their ability to suction liquid both on land and underwater.
Working with veterinarians at Zoo Atlanta, the researchers investigated the inner machinations of the elephant trunk by watching elephants as they ate various foods. Not a bad study for the elephants, then, but one that would’ve had people with misophonia clawing at their ears as it centered around observing if and how elephants could suck up solids and liquids using their trunks — AKA, slurp central.
The sucking skills of the elephant trunk were indeed confirmed, using snacks including rutabaga cubes (a type of root vegetable) and tortilla chips. The elephants were able to suck up the cubes and tortilla chips, with some even holding the chips to their trunks by inhaling (a bit like a person sucking a piece of paper over their mouth). Using suction to hold food was believed to be a behavior limited to fish, demonstrating once again that elephants really won big in the evolution lottery.
As well as being proficient in hoovering up light foodstuffs, the research showed that elephants are capable of dilating their trunks to fit in a surprising volume of liquid. To work out how they were doing it, the team used ultrasonographic imaging and an ultrasonic probe. This revealed that when an elephant sucked up viscous fluids, they could dilate the trunk 30 percent in radius, bumping up nasal volume by 64 percent. Based on the pressures applied to the ultrasonic probe, the teams estimated a sucking speed of over 150 meters (492 feet) per second, which they say is nearly 30 times the speed of a human sneeze being exhaled. A video from the study shows an elephant sucking up 3.7 liters in just 1.5 seconds, inducing a noise that sounds magnificently ridiculous when replayed in slow motion, so make sure your sound is on.
"An elephant eats about [181 kilograms] 400 pounds of food a day, but very little is known about how they use their trunks to pick up lightweight food and water for 18 hours, every day," said Georgia Tech mechanical engineering PhD student Andrew Schulz, who led the study, in a statement. "It turns out their trunks act like suitcases, capable of expanding when necessary.
“At first it didn't make sense: an elephant's nasal passage is relatively small and it was inhaling more water than it should. It wasn't until we saw the ultrasonographic images and watched the nostrils expand that we realized how they did it. Air makes the walls open, and the animal can store far more water than we originally estimated."
It’s hoped that these insights into the many talents of the elephant’s trunk could be applied to innovations in technology including soft robotics. As an added bonus, learning more about these endangered animals and how they feed could also inform conservation efforts working to protect their future.
