Despite their massive size and 100-kilogram trunks, elephants feed on small, lightweight vegetation, prompting the question: how do they hoover such small items up their long trunks?
According to a new paper in Interface, a team of researchers from the Georgia Institute of Technology, US, have filmed elephants at Zoo Atlanta in the hopes of demystifying the mechanics behind their powerful schnoz.
The team observed the elephants consuming their food, recording the width of the nasal passage during suction and measuring the rate of siphoning of water. They were able to demonstrate for the first time that elephants do in fact use suction to grab food – a behaviour the authors say was previously thought exclusive to fish.
Elephant sucking up liquid. Credit: David Hu.
The researchers found that elephants can dilate their nostrils to increase the volume by 60%, and can inhale at speeds over 150 metres per second, almost 30 times the speed of a human sneeze.
According to the paper, many marine animals use suction force as part of their suite of adaptive behaviours: the clingfish uses a modified pelvic disc to stick to slippery rocks, and many fish species use suction feeding to hoover up their food, but the morphology associated with this type of feeding tends to include a mobile skull which is not a common feature among land animals.
Nonetheless, despite their notably different skull morphology, this new evidence proves that elephants can deploy suction in much the same way. The authors suggest that the mechanics they’ve uncovered could inspire future innovations in robotics, building on the already significant elephant-inspired robotic repertoire.
Elephant trunk-inspired robots already developed or designed include one that can perform autonomous refuelling of ships, and another that can transport air or water to victims of disaster trapped under debris and rubble.
The new study builds on the cross-disciplinary field of bio-inspiration, in which scientists from different disciplines collaborate to produce technological innovations inspired by the evolutionary idiosyncrasies found in nature.
Elephant picking up a Tortilla chip. Credit: David Hu.
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