In Prehistoric Ethiopia, Otters Were as Big as Lions

Some a few million several years ago, one of our early hominin ancestors was chowing down on some leaves along a riverbank in what is now Ethiopia. And there it was—440 kilos of fur, with teeth strong sufficient to crush bone. An otter the dimension of a large male lion ambled by the dense grasses prior to bending down to consume from the muddy riverbank. Our ancestor, we figure, crept back again into the encompassing woodlands. It does not make a difference how probably lovely the giant otter may possibly (or may not) have been, you just do not want to cross an animal that dimensions.

The otter, Enhydriodon omoensis, is the most significant ever identified. A new analyze in the French journal Comptes Rendus Palevol is the initial to classify the species, naming it right after Ethiopia’s Omo River, the place its continues to be were uncovered. Although the research calls the otter “lion-sized,” paleontologist Margaret Lewis of Stockton College in New Jersey thinks “that’s kind of underselling it.” “Bear otter,” she says, is probably a far better term to encapsulate just how massive these otters had been. All right, grizzly otter it is.

But the otter’s huge size was not the only factor that shocked the direct author of the study, carnivore professional Camille Grohé of the University of Poitiers in France. Testing on oxygen and carbon isotopes collected from the otter’s teeth shows that, in contrast to its semi-aquatic contemporary descendants, Enhydriodon omoensis lived generally on land. “I genuinely did not assume that,” states Grohé.

The first fossil expedition to the Lower Omo Valley was in the 1930s. Since 1967 it has been the site of almost continuous scientific digs.
The very first fossil expedition to the Lessen Omo Valley was in the 1930s. Because 1967 it has been the web-site of nearly ongoing scientific digs. Courtesy Omo Team Investigation Expedition (OGRE)

Nestled in the southwest corner of Ethiopia, the Reduced Omo Valley is a paleontology celebrity. Not significantly from the place the fragmentary remains of Enhydriodon omoensis ended up found, paleontologists, typically with the assistance of locals, have uncovered various fossils belonging to our early hominin ancestors. “The Omo Valley is one particular of the earliest identified [sites] of paleontological significance,” claims Ethiopian paleontologist Yohannes Haile-Selassie of Arizona Point out College. As much back again as the early 1900s, European explorers describe seeing fossils dotting the hillsides along the Omo River. Then, in 1967, an global crew of researchers surveyed the area “and that is when they started off getting all kinds of matters,” suggests Haile-Selassie. Between people finds, in the early 1970s, was a large femur. “[Researchers] knew it was some sort of a carnivore, but it was as well large, they did not consider it was an otter. So it’s been there in the collection” at the Nationwide Museum of Ethiopia ever since, provides Haile-Selassie. The Countrywide Museum, in Addis Ababa, properties 1000’s of fossils uncovered from the Omo (like the fossilized stays of a particular hominin we know right now as “Lucy”). In April 2019, Grohé went digging for ancient carnivores—in the museum’s fertile storage space.

“That’s the place you locate really cool stuff, in museums,” says Grohé. For about 3 months, Grohé labored in the museum’s basement, analyzing the hundreds of Omo carnivore fossils. “I was not just on the lookout at otters,” she suggests. “I was on the lookout at total diversity [and] examining if the specimens we experienced in the database also matched the specimens we had in the drawers.”

Finally, she arrived throughout a “weird” femur, the very same just one paleontologists uncovered back again in the 70s. It appeared to occur from an otter, but it was genuinely, genuinely lengthy and that didn’t genuinely match an aquatic mammal,” which have typically shorter femurs to assist the animals swim. Grohé picked out a couple other fossils—some teeth and bits of the cranium—that also didn’t seem to match any acknowledged species of otter.

The prehistoric giant otter weighed almost five times as much as <em>Australopithecus afarensis</em>, the hominin species that
The prehistoric big otter weighed almost 5 occasions as much as Australopithecus afarensis, the hominin species that “Lucy” belonged to. © Sabine Riffaut, Camille Grohé / Palevoprim / CNRS – Université de Poitiers

In July 2019, Grohé returned to Ethiopia, and this time went to the Decreased Omo Valley to see in which the fossils experienced been uncovered. “It’s a lengthy strategies,” claims Kevin Uno of Columbia College, a different creator on the analyze. “Imagine driving across the point out of Utah devoid of a one paved street.” With 10 vehicles filled with paleontologists and materials, it normally takes 4 times to reach the Omo from Addis Ababa. Nestled alongside the chai-colored river, the arid valley is dotted with spectacular hills. “It seems to be like the Badlands in South Dakota,” claims Uno.

Whilst the paleontologists appeared for fossilized carnivores, armed protection personnel retained their eyes peeled for their dwelling brethren. Lions stalk the grasses crocodiles prowl the river. One morning in 2014, Uno remembers looking at the footprint of a lion stamped into the team’s refreshing tire tracks.

The good news is, Grohé averted any operate-ins with residing carnivores in 2019. As a substitute, she identified some fossilized big oysters. Guessing that Enhydriodon omoensis was semi-aquatic, “I imagined that could be a very good food for this otter,” she claims. But when she analyzed some of the otter’s enamel back again at her lab, she discovered some thing astounding.

Collaborating with Uno, Grohé and a workforce of scientists extracted tiny amounts of enamel from the Enhydriodon omoensis’s tooth, which they tested for carbon and oxygen isotopes. Grohé was astonished to obtain that the isotopes had been from largely terrestrial resources. “It was feeding on a extensive assortment of [land-based] prey,” says Grohé the patterns have been identical to individuals observed in significant cats and hyenas today. But regardless of whether the otter was hunting or scavenging, Grohé isn’t positive.

Almost 500 miles long, the Omo River winds through southwestern Ethiopia.
Practically 500 miles extended, the Omo River winds by way of southwestern Ethiopia. Rod Waddington/CC BY-SA 2.

Enhydriodon omoensis wasn’t the only big otter in Africa in the course of the Pliocene and late Miocene, about seven million to two million years ago, but it was a person of the previous. “I predicted it to have a very slim array of habitat that could probably describe why it went extinct,” claims Grohé. Offered that the otter experienced a significant habitat and could try to eat just about nearly anything, “I know a lot less now why she went extinct.”

Lewis can take that concern a step further—if a generalist like Enhydriodon omoensis didn’t make the evolutionary lower, how did our human ancestors regulate to endure? “It’s scary adequate if you just believe about surviving with lions and hyenas and leopards and all the living stuff,” but when you include in three species of saber-toothed cats, these big otters, and all the other terrifying factors of the Pliocene, “it’s wonderful that [our hominin ancestors] came by way of this,” she suggests.

Grohé is not confident precisely what would’ve happened in an experience amongst our early ancestors and Enhydriodon omoensis. “I never know if it would’ve been necessarily aggressive toward you,” suggests Grohé. But however, she states, “I imagine, like [with] a bear, you really do not strategy it.” Uno agrees, joking, “If I were being to face this otter, I would have desired our experience to be at a length.”

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