Europe’s last pandas were giant weaklings who couldn’t even eat bamboo

Around 6 million years ago, the ancestors of bears vanished, perhaps as a result of a drastic climatic shift.

When pandas last roamed Europe was recently revealed by a pair of fossilized teeth in a museum collection.

The fossilized teeth, which had been preserved for around 40 years, were analyzed by scientists, who found that they belonged to a hitherto unidentified species of ancient European pandas. The recently discovered species, which is closely related to contemporary giant pandas, possibly represented the last of Europe's pandas and inhabited the continent approximately 6 million years ago.

Originally discovered in the late 1970s from a location in northwest Bulgaria, the teeth—an upper canine and an upper molar—were eventually stored in the Bulgarian National Museum of Natural History in Sofia. The teeth were neglected for many years since they were never properly cataloged. However, when museum employees recently came upon the curious teeth, they made the decision to look into it more.

The fossils were unlike any other panda species teeth previously reported in Europe, but analysis of the teeth revealed that they belonged to an ancient European panda. Since the majority of European panda species have smaller teeth than contemporary giant pandas (Ailuropoda melanoleuca), they were most likely substantially smaller than their contemporary relatives. However, the newly discovered species, called Agriarctos nikolovi, has far bigger teeth than typical for European pandas, indicating that it was probably comparable in size to modern giant pandas. The teeth's far more recent age compared to other panda fossils found in Europe, some of which go back more than 10 million years, indicates that A. nikolovi was probably the final panda species to inhabit the continent.

Paleontologist Nikolai Spassov of the Bulgarian National Museum of Natural History, a research co-author, stated in a statement that "this discovery reveals how little we still know about ancient nature" (opens in new tab). It also "demonstrates that historic discoveries in paleontology may lead to unexpected conclusions, even today," according to Spassov, since the newly named species stemmed from a specimen discovered in the 1970s.

A. nikolovi and existing giant pandas are comparable in size, but the newly discovered species "is not a direct progenitor of the present genus," according to Spassov. It is, nonetheless, a near relative. He went on to say that the new species most likely inhabited a completely distinct environment from that of modern pandas.

The fossilized teeth were initially discovered in coal seams, where the bears' canines had partially become black. The coal at the location has a composition that indicates the region was originally a marshy woodland. This suggests that A. nikolovi may have consumed a wider variety of soft flora than current pandas do, as opposed to relying solely on one kind of plant, like bamboo, which is the preferred dietary of modern pandas.

Although their digestive processes resemble those of other bears, it's interesting to note that gigantic pandas only consume vegetarianism. According to the statement, previous studies have shown that giant pandas shifted to a diet of bamboo because they were outcompeted by other bears. Given that A. nikolovi's teeth are much weaker than those of modern pandas, which means they could probably not even chew through bamboo, let alone something as hard as animal bones, the researchers believe that A. nikolovi may have also experienced similar evolutionary pressures to adopt a vegetarian diet.

The authors of the study hypothesize that A. nikolovi's habitat and food may have been impacted by climate change, which may have ultimately led to its extinction.

The final European panda's survival was presumably negatively impacted by climatic change near the end of the Miocene period [23 million to 5.3 million years ago] in southern Europe, according to Spassov. The "Messinian salinity crisis," when the Mediterranean Sea nearly dried up, which had detrimental effects on land ecosystems, occurred approximately 6 million years ago. The researchers hypothesized that A. nikolovi may have been particularly sensitive to this occurrence. According to the statement, the marshy woodlands where the old pandas lived probably grew considerably drier and warmer, making it more difficult for vegetation to thrive and probably starving the pandas.

The research team is still unsure about the precise relationship between big pandas and prehistoric Asian pandas and A. nikolovi and other extinct European pandas. It is still unknown if pandas initially lived in Asia before migrating to Europe, or the other way around. Because fossil data indicates that "the oldest members of this group of bears were located in Europe," Spassov added, the researchers believe that pandas originated in Europe. The latest fossils, however, are from the youngest of Europe's long-extinct pandas, so they are unlikely to provide any answers to this specific puzzle, according to the experts.

The study was published online July 31 in the Journal of Vertebrate Paleontology