An elephant trunk can perform a range of large and fine motor skills thanks to "fingers" at the tip of the trunk. Researchers from the Humboldt University of Berlin and the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) examined the facial motor nucleus of the elephant facial nucleus. The findings, published in Science Advances, highlight how this brain structure controls the facial muscles that run from the ears to the tip of the trunk.
The elephant’s facial motor nucleus contains more facial motor neurons than other terrestrial mammals. The scientists counted about 54,000 neurons in the facial nucleus of Asian elephants (Elephas maximus), whereas the African savanna elephant (Loxodonta africana) has about 63,000. This, the scientists observed an association between the amount of medial facial subnucleus neurons and the extent of ear-motor control. African savanna elephants possess two finger-like appendages at the trunk tip that can grasp objects. This pincer like feature uses prominent neuron clusters for trunk control whereas Asian elephants have one finger and frequently wrap their trunk around objects. Brain imaging shows the Asian elephant's fingertip is less prominently represented in the brain.
The unique brain structure of the elephant provides a helpful example of how the brain adapts to environmental factors. According to study author Dr. Michael Brecht, “The elephant facial nucleus is one of a kind. It’s not just the huge number of neurons. We also observed size gradients of neurons along the trunk representation that we do not see in other mammals. The observed giant elephant neurons probably arise from the need to extend very long signaling structures into the trunk.” Discovery of how neural adaptation of elephant brain may provide the groundwork for researching human neuroplasticity.