Elephants don’t often come across delicate tortilla chips at their regular watering holes, but if they did, they’d have no trouble picking them up with their trunks without breaking them. Presenting their research at the annual meeting of the Society for Integrative and Comparative Biology in New Orleans, scientists reveal that elephants use a special trick to alter the amount of force they exert with their trunks on items as they lift them, enabling them to handle both heavy and dainty objects with ease.
The team placed chunks of food of varying weights and sizes on a scale, and measured the amount of force that elephants at Zoo Atlanta exerted as they picked them up with their trunks. They also filmed the animals in order to get a better look at how they adjust their trunks to ensure they use the appropriate force for each item.
It turns out that elephants make a bend in their trunk when grabbing things from the floor, and that by changing the location of this bend they can precisely control the amount of pressure they exert.
This is because they only use the weight of the latter part of their trunk to grab with, so by creating the bend near to the bottom of the trunk, they minimize the amount of strength used to grasp an item, thereby ensuring they don’t crush it.
Conversely, when lifting heavy, robust objects like large logs, they bend their trunks near to the top, which allows them to exert more force.
Using this technique, one elephant named Kelly was even able to pick up a tortilla chip without damaging it. According to the researchers, she used only 5 percent of the weight of her trunk to seize the chip, which is less than half the weight that blindfolded humans use to lift items.
The researchers say this technique could be used to create robotic grippers with the capacity to alter the amount of force they exert in accordance with the objects they are grasping.