Just as people naturally favor their left or right hand, elephants have their own version of handedness. But instead of having a dominant limb, they have a preference for the direction in which they typically bend their trunks. Although only 10% of people are left-handed, elephants are more equally divided, with roughly 50% “right-trunkers” and 50% “left-trunkers.”
In a recent study, German researchers found that clues on the trunk itself reveal whether an elephant typically scoops objects toward the left or right side of its body. By studying the appearance of the wrinkles and whiskers that cover an elephant’s trunk, they were able to make an accurate assumption about its "trunkedness."
Baby elephants, however, appear to have symmetrically wrinkled trunks, so it seems likely that the arrangement of wrinkles and whiskers develops over time due to trunk use. More skin creases form as the trunk repeatedly curls in one direction, potentially making that side more flexible and better able to bend and grasp. For instance, left-trunkers typically have longer whiskers and more wrinkles on the left side of the trunk because the whiskers on the right side will have worn down from rubbing against the ground.
The inspiration for the research came when neurobiologists at the Humboldt University of Berlin noticed a small, striped bump on the brain stems of both African savanna elephants and Asian elephants that is not apparent in other mammals. The stripes turned out to be bundles of nerve fibers corresponding to the number of wrinkles on the elephant’s trunk.
The researchers made other significant discoveries in their study of elephant trunks, including important differences between Asian and African elephants. Asian elephants have many more trunk wrinkles than African elephants, which the researchers believe makes their trunks more flexible. This is important as Asian elephants use their trunks to wrap around objects, like large fruits. African elephants have slightly less flexible trunks and instead use the two finger-like appendages at the end of their trunks to pinch, grasp, and manipulate objects.
Wrap your mind (or trunk) around this:
- An elephant’s trunk (scientifically known as a “muscular hydrostat”) has around 40,000 muscles—the most of any body structure in any mammal. By comparison, the human body has around 600 muscles.
- Most of an elephant’s wrinkles are developed before birth. Between day 80 and day 150 of gestation, the number of trunk wrinkles doubles every 20 days before slowing down for the rest of the 22-month-long gestation.
- Some wrinkles are accumulated during adulthood. In the study, newborn African savanna elephants averaged 87 wrinkles, while older adults averaged 109.
