The water absorption speed is equivalent to 24 shower heads! Is there anything that an elephant's trunk can't do?

At Zoo Atlanta, a female African elephant named Kelly faces a challenge with strange foods.

On the platform in front of him was a strange food he had never seen before: it was round, thin, and smelled a little fragrant - it was a Mexican crispbread. The crispbread, only 0.5 mm thick, was stuck to the smooth surface and was difficult to pick up. It would break if he applied a little force. This was probably the most difficult food Kelly had ever seen.

Surprisingly, Kelly completed the difficult challenge on the first try, grabbing the cookie and stuffing it into his mouth without any damage, and the whole process took only 3 seconds.

Can't catch it? No way | Provided by researchers

How does she do it? The answer is the powerful suction of her trunk.

Is the food too hard to grab? Just suck it

Kelly was a subject in a scientific study, where researchers hoped to gain deeper insights into the remarkable capabilities of an elephant’s trunk.[1]

Normally, African elephants use their trunks to grab grass, leaves, fruits, bark and other foods. This study found that when grabbing becomes difficult, elephants will use their suction to suck up food. This ability to grab food through airflow is very rare among terrestrial mammals.

Kelly the African elephant | Zoo Atlanta

In the study, people set up a variety of food challenges for Kelly, such as a series of small food cubes of different numbers and sizes. The results showed that when faced with larger food cubes in smaller quantities, elephants would control the front part of their trunks and grab the food like a hand. If the food blocks are small in size and large in number, making it difficult to "grab them in one hand," the elephants would take a deep breath and collect the food into their trunks. However, if the food is very small particles like bran, the elephants would give up sucking it and switch back to eating by grabbing. This choice not only improves eating efficiency, but also helps elephants avoid inhaling particulate foreign matter.

Too many small pieces of food? Use suction to catch them all | Provided by researchers

Even if the food is as light, fragile and unfamiliar as a wafer, the elephant can still successfully eat it by sucking it in. High-speed video shows that the trunk first lifts the wafer by sucking air, and then holds it firmly.

Suck fast, fill more

How strong is the suction power of an elephant's trunk? The researchers calculated this based on their measurements of the process of an elephant's trunk sucking water.

The results showed that elephants can absorb water at a speed of 3.7 liters per second, which is equivalent to turning on 24 shower heads at the same time, or flushing 20 toilets at the same time. When they inhale, the instantaneous speed of the airflow can reach 50 meters per second - which is almost 30 times the speed of the airflow when a person sneezes.

The elephant's trunk sucks water. Chia seeds were added to the water to show the flow of water | Provided by researchers

The elephant's powerful suction is not only based on lung capacity, but also on the structural characteristics of its trunk. The trunk is not a fixed "straw". It can expand rapidly when sucking liquid: the radius of the nostril can expand by up to 30%, and the volume of the nasal cavity can expand by up to 64%. The expandable nostril can not only store more water, but also help accelerate airflow, providing favorable conditions for sucking hard-to-grasp food.

Not only that, the inner wall of the elephant's nasal cavity is also different from that of other animals. Wu Jianing, co-first author of the paper and a researcher at Sun Yat-sen University, told Guokr that they analyzed the structure of the elephant's nasal cavity and compared it with that of many other mammals - even including Wu Jianing's own nostrils. Observations show that the inside of the nasal passages of most mammals are rough and even have nose hairs, while the nasal passages of elephants are exceptionally smooth. In this way, the airflow in the nasal cavity is unobstructed, making it easier to form a sufficiently large negative pressure to facilitate the absorption of various things.

The flexible and soft elephant trunk has always been an object of study and imitation for engineers. Research on the suction ability of the elephant trunk can also provide a reference for the design of new bionic soft robots.

References

[1] http://rsif.royalsocietypublishing.org/doi/10.1098/rsif.2021.0215

[2] https://www.sciencedaily.com/releases/2021/06/210601194151.htm

[3] https://www.nytimes.com/2021/06/01/science/elephant-trunks-suction.html

Author: Window Knocking Rain

Editor: Luna