The elephant trunk is a marvel of evolution. It combines the nose and upper lip, contains over 40,000 muscles, and has no bones. Elephants can use their trunks to knock over a tree or gently pick up a banana. The trunks of Asian and African elephants are slightly different. African elephants have two cartilage "fingers" on their trunks, while Asian elephants have only one. A recent study out of Humboldt University of Berlin focused on their wrinkles.
It turns out that even their wrinkles are fascinating. Scientists found that while the wrinkles begin to form in the womb, they develop further after birth. The wrinkles can even determine "trunkedness," or whether an elephant favors using their trunk towards the right or left side.
To study how these wrinkles form, the team gathered two Asian and three African elephant fetuses in museum collections, along with dozens of published photographs or drawings of fetuses at different ages. By lining these up sequentially, the researchers were able to form a visual timeline of prenatal trunk development. Wrinkles, they found, begin to appear as soon as the trunk does—about 20 days into the elephant's 22-month gestation. Over the next 150 days, the number of wrinkles increases exponentially in both species, doubling every 3 weeks, and concentrates around the pivot point. Asian elephants acquire even more wrinkles later on in development.
The scientists next looked at whether trunk use contributes to additional wrinkle formation, as they originally suspected. Elephants are either left- or right-trunked, meaning they consistently bend the appendage to one side to put food in that side of the mouth. Over time, the researchers found, this bending creates more wrinkles on one side than the other.
Scientists still don't know if the wrinkles present from birth predispose right or left-trunkedness or if some other mechanism is involved. They also theorize that Asian elephants have more wrinkles to compensate for having only one "finger."
Side note: The Elephant Nature Park in Chiang Mai, Thailand, where the photo above was taken, recently suffered a catastrophic flood during which two elephants were lost. This wonderful organization rescues and rehabilitates elephants from logging and tourism and gives them a safe place to live out the rest of their lives in peace. They also rescue dogs, cats, horses, goats, buffalo, pigs, and other animals. Find out more or donate to the organization here.
Previously: Elephants greet each other by "saying hello" and gesturing
