Scientists have discovered a new ability of the elephant trunk

The trunk of elephants is a biological wonder. With no joints or bones, the trunk is a muscular appendage with the power to uproot a tree or slowly pull out each leaf, and moreover, a more developed sense of smell than a dog's minesweeper. cop.

Indeed, elephants use their trunks for many different things. They use the hose to drink, hold and spray water, as well as blow air through to communicate – with a 110 decibel sound that can be heard from miles away.

'It's like a multi-purpose tool from a muscle,' Andrew Schulz, a graduate student in mechanical engineering at the Georgia Institute of Technology, said. In the study, published in May in the journal Royal Society Interface, Schulz and his colleagues detailed how elephants do something else: use gravity to get food - a behavior which previously belonged only to fish.

While popular in children's books or nature documentaries, there are still many gaps in our scientific understanding of the biology of the trunk, which studies like this could possibly lead to. complementary. For example, according to Schulz, the most recent detailed description of the anatomy of the trunk was a hand-drawn monograph published in 1908.

Contrary to popular belief, the trunk does not act like a straw. 'In fact, what they do is draw water into the trunk and store it,' said Mr Schulz. 'So the trunk's role is like a suitcase.'

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Mr. Schulz completed his research in the lab of mechanical engineering professor David Hu, with the main theme of how animals move and act, and aimed to apply these discoveries to solve engineering problems. human art. One reason we don't study elephant anatomy enough is because it's very difficult to work with, he said. 'They are really strong, a lot of people underestimate their strength,' he said. 'We used to do our experiments at the zoo, where they smashed the devices.'.

During their work with Zoo Atlanta, the researchers recorded how Kelly - a 3.3-ton female African elephant - picked up a variety of food. When presented with small rubataga bulbs, the elephant inhales air through the trunk to create suction to pick up food. But if the rubatagas given were larger, or less numerous in number, Kelly mostly used two opposite knobs at the tip of the spout to pick them up. The elephant also uses these two nodules to pick up handfuls of bran, possibly to avoid inhaling these fine particles.

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But when faced with the most difficult food the researchers put on the table, Kelly had to use gravity to pick it up: a piece of tortilla. Although the cake was fragile and difficult to reach on a flat surface, Kelly was able to use gravity to lift and pick up the piece without breaking it.

The answer to elephants' strong attraction seems to lie in their large nostrils and specialized respiratory system. Using a non-invasive ultrasound probe, researchers have found that elephants can dilate their nostrils and increase nasal volume by up to 64% when aspirated with bran water and can store up to 6 liters of liquid in the faucet. After measuring the speed at which the elephant can use its trunk to suck in water, the researchers calculated that the elephant's nose can inhale at more than 150m/s, or 30 times the speed of air through a human's nose when sneezing.

Although fish have long been known for their sucking abilities, according to Schulz, elephants appear to be the only land animals that can 'master the ability to follow liquids, both underwater and above water'. .

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Dr. Michael Garstang, Professor Emeritus at the University of Virginia and author of the book Elephant Sensation and Sensitivity, noted that we have not yet determined whether elephants in the wild are real. does the act of eating using such suction. Elephants use their trunks to store backup water so they can drink and cool down. Dr. Garstang said: 'So they won't want to mix it with dirt, leaves or other things.'. African elephants also eat about 200 kilograms of vegetables a day by grabbing handfuls of leaves before stuffing them in their mouths, much more efficiently than having to hand each handful.

Still, he says the new research could have useful technological applications for robotics. Animal appendages such as elephant trunks and octopus tentacles have already inspired many innovations in soft robotics, a fledgling industry that relies on flexible designs without joints. This study shows how elephants 'adapt both air and water to manipulate different objects', a task that robotics has still struggled to accomplish, Schulz said.

More detailed biological studies of elephants like this will also improve conservation efforts for two species of African elephants, which are at risk of disappearing from the wild because of habitat loss and deforestation. poaching. Savanna elephants are critically endangered, while forest elephants are critically endangered, with populations having fallen by more than 86% in the past three decades alone. A lot of trauma to elephants by poachers focuses on the trunk, so a better understanding of this part could improve the recovery of injured animals.

Mr Schulz said: 'What I hope is that people can read this research and be inspired to work with elephants, and be inspired to do their conservation.'.

Jessica Tanner

Update 27 July 2021