Evolution: elephant trunk and nerve controls: (Evolution)

by David Turell , Monday, October 31, 2022, 22:42 (543 days ago) @ David Turell

A study of African and Asian elephant nerve controls of trunks:

https://www.smithsonianmag.com/smart-news/what-an-elephants-brain-reveals-about-its-tru...

“'As you might have expected because of their size and because of elephants’ very special facial abilities, there are six times more neurons that innervate the musculature of the elephant face compared to humans,” co-author Michael Brecht, a researcher at Humboldt University of Berlin, tells the Wall Street Journal’s Dominique Mosbergen.

"The team examined four Asian elephant (Elephas maximus) brains and four African savanna elephant (Loxodonta africana) brains, and they found that about half of elephants’ facial neurons are dedicated to the trunk. And the brain cells that controlled the tip of the trunk’s movement are larger than those associated with the parts of the trunk that are closer to the face.

"But between the two elephant species, the researchers found some major neural differences. For one, they used their trunks differently, a contrast reflected in their brains. An Asian elephant has one “finger” at the trunk’s tip, so it will pick up an object by wrapping the entire trunk around it. African savanna elephants, on the other hand, have two of these fingers, which they use to hold items.

“'This kind of pincer grip requires much dexterity with the trunk tip,” co-author Thomas Hildebrandt from the Leibniz Institute for Zoo and Wildlife Research says in the statement. “Not surprisingly, we see in the brains of African elephants prominent neuron clusters for the control of the fingertips.”

"The ears, too, differed between the species. African elephants have roughly 63,000 facial neurons, of which about 12,000 are used to control their ears. The Asian species, meanwhile, has some 54,000 facial neurons, with about 7,500 of them used for ear movement. This may partially be because of the animals’ physical differences: Asian elephants have smaller, rounder ears than their African relatives.

“'It’s a beautiful example of how species’ diversity in brain structure maps to a body’s specialized anatomy,” Chet Sherwood, a biological anthropologist at George Washington University who was not involved with the study, tells the Wall Street Journal."

Comment: this is a no-surprise result, knowing what we know ab out elephant trunk dexterity.