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It Takes a Lot of Elephant Brains to Solve This Mystery

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An elephant’s trunk has 40,000 muscles and is strong enough to uproot a tree yet sensitive enough to suction up fragile tortilla chips.

But how does an elephant’s brain help accomplish these feats? That has been difficult to study, according to Michael Brecht, a neuroscientist at the Humboldt University of Berlin. Weighing in excess of 10 pounds, the elephant’s brain degrades quickly after death.

Brecht and his colleagues were fortunate enough to gain access to a trove of elephant brains from animals that had died of natural causes or were euthanised for health reasons and ended up either frozen or in a fixative substance at the Leibniz Institute for Zoo and Wildlife Research in Berlin.

In a recent study in the journal Science Advances, the researchers reported elephants had more facial neurons than any other land mammal. The study also helped to pinpoint major differences between the neural wirings of African savanna elephants and Asian elephants.

Using the brains of four Asian elephants and four African savanna elephants, the researchers homed in on the facial nucleus, a bundle of neurons concentrated in the brainstem. In mammals, these neurons serve as the control centre for facial muscles.

The researchers divided the facial nucleus into regions of neurons that controlled the elephant’s ears, lips and trunk. African elephants sported 63,000 facial neurons, while their Asian cousins had 54,000.

Brecht’s team expected both African savanna and Asian elephants to possess massive stores of facial neurons.

While the animals look similar, they have major facial differences. African elephants have much larger ears, which they fan out when they charge. The researchers found a neurological correlation — African elephants devoted roughly 12,000 facial neurons to controlling just their ears. This not only dwarfs the amount of neurons controlling Asian elephant ears, it is nearly 3,000 more neurons than are needed to operate the entire human face.

Another major difference is how each elephant wields its trunk, which requires nearly half of the elephant’s total facial neurons to operate. African elephants utilise two fingerlike projections on the tips of their trunks to pinch objects. Asian elephants have only one fingerlike projection and grasp objects by wrapping their trunks around them. The researchers pinpointed two neural regions in African elephants that probably correlated to fine finger control at the tips of their trunks; those regions were less defined in Asian elephants. — NYT