It was what the military calls an enveloping maneuver. After 2.5 million years thriving throughout Eurasia, including the Iberian Peninsula, the woolly rhinoceros (Coelodonta antiquitatis) retreated further and further east and further north, pursued by bad weather and finished off by Neanderthals and, especially, by modern humans. In the end, when the ice age had passed and the planet entered the current era, as happened to the mammoths and most of the megafauna, only a few remained in the extreme northeast of Siberia. They did not cross to America through the Bering Strait, they became extinct before. Now, the modeling of that retreat has made it possible to distribute the blame: the climatic fluctuations made its coffin and human hunting put the nails. The authors of this research believe that four of the five remaining rhino species are also on the same highway to extinction. But they have a few exit routes left.
The extinction of most of the megafauna (in a loose sense, animals weighing more than 1,000 kilograms) of the late Pleistocene is one of the biggest enigmas that has complicated the lives of paleontologists. Mammoths, glyptodonts, mastodons, woolly rhinos, cave bears… and so on, up to about 65 species existed long before the last ice age began (about 126,000 years ago). They were still on Earth when modern humans began their expansion from Africa, reaching western Europe about 55,000 years ago. For millennia, Neanderthals, Sapiens and various large species, both megaherbivores and carnivores that would make the lion a big cat, shared space. But at the end of this period, whose end was marked by the end of the glaciation, about 12,000 years ago, giving way to the warm period of the Holocene, one could count on the fingers of one’s hands the species of large animals that remained. Today, leaving aside the European and American bison, only hippopotamuses, elephants and rhinoceroses remain in Africa and other species of the second two in South Asia. Studying the woolly rhinoceros could help us learn what happened to the other extinct rhinos and what awaits those that remain.
Researchers from several European, Australian and Chinese universities have compiled hundreds of references to woolly rhinoceros remains (whether in the fossil record, in the form of bones, or their ancient DNA) from the last 52,000 years to feed a model in which they also They included the evolution of the climate in Eurasia (this animal lived from the Iberian Peninsula to the extreme east of Asia). They completed it with the presence also in the fossil record of Neanderthals and the progressive occupation of the territory by modern humans. The dating and location of each record has allowed them to draw a dynamic map with the evolution of the distribution of these rhinoceroses. The map and all the work, published in the scientific journal PNAS, shows that climate change did not kill them, as the Tyrians defend. Neither did the different human species, as the Trojans claim. It was both.
“We gave it the coup de grace, but it was a species that was already very sick, it had entered into negative, recessive dynamics, mainly due to climate change,” says the professor at the University of Copenhagen (Denmark) and co-author from the studio, David Nogués. When modern humans arrived and expanded across Eurasia, in the middle of the Ice Age, they incorporated megaherbivores such as the mammoth or the woolly rhinoceros into their diet. But the fossil record does not detect a significant decline in animal populations until many millennia later. “We detect the differences when the planet goes towards the maximum glacier,” he adds. The last ice age, called the Würm glaciation, had a cold peak between 26,000 and 20,000 years ago, when the ice in the northern hemisphere fell to the upper edge of what is now the United States and in Europe, as far as Germany. And further south, hundreds of kilometers of permafrost. “What happened to the ecosystems is that plant productivity collapsed. That meant that the herbivores had less to eat,” adds Nogués.
The coffin was already ready. Rhinos are disappearing from Europe and almost all of Siberia, being restricted to the southern Siberian strip, the Tibetan plateau and, in the extreme north, Beringia. The fossil record also detects a growing consumption of this animal by modern humans, who in addition to spears have incorporated arrows and other projectiles into their hunting weapons. It is summarized by the professor at the Environmental Institute of the University of Adelaide (Australia) and first author of the study, Damien Fordham: “Since about 30,000 years ago, a combination of cold temperatures and low but sustained levels of hunting caused the distribution of woolly rhinos to the south, trapping them in isolated and rapidly deteriorating habitats until the end of the Ice Age.”
“As the Earth thawed, woolly rhino populations were unable to colonize the new habitats that were opening up in northern Eurasia.”
Damien Fordham, Professor at the Environmental Institute at the University of Adelaide, Australia
But the lid of the coffin was a matter of the weather, this time in the opposite direction. After the glacial maximum, a slow warming of about 10,000 years begins. The ice is retreating, freeing large areas that were once again available for megaherbivores. “As the land thawed and temperatures rose, woolly rhino populations were unable to colonize the new habitats that were opening up in northern Eurasia, causing their populations to destabilize and collapse, leading to their extinction.” Fordham details. The authors acknowledge not knowing exactly what happened, but woolly rhinos no longer appear in the fossil record in most of the territory they once occupied. Here they introduce elements of ecological theory to explain it: the groups that remain were in a fragmented habitat, isolated. From what is known from current rhinos, their mobility is very limited and with fragmentation, genetic exchange between populations is reduced, which must have reduced their ability to adapt to environmental changes. And each generation, the numbers were reduced by hunting.
The last woolly rhinos survived, like mammoths, in the far northeast, on the Asian side of the Bering Strait. During the glacial maximum, Beringia remained relatively ice-free and became a climatic refuge. But the species was already doomed. The last specimens of this species became extinct just over 9,000 years ago.
“The highway that drove the woolly rhino to extinction is where the rest of the rhinos are found.”
David Nogués, researcher at the University of Copenhagen, Denmark
“Extinctions are not the extinction of the last individual. They are not an event, they are a process,” highlights Nogués. “There are different highways that take you towards extinction. There is not just one, but what we know is that what led to the extinction of the woolly rhinoceros is the one in which the rest of the rhinoceros species are found, with the same processes: habitat fragmentation, hunting, incapacity of populations to connect…”, he adds. And this happens in the black rhinoceros and the three Asian species. The northern white subspecies is virtually extinct with only two specimens remaining in captivity. But the Spanish researcher also highlights that, on this occasion, there is a factor that was not present in the past, human awareness of their responsibility and their ability to provide an alternative to these animals that seem to come from prehistory: “There is a species, the white rhinoceros, whose southern population was barely 100 animals a century ago and now there are more than 18,000 specimens. It is one of the classic examples that, when you put money, desire, resources, means, political decisions, you can recover the natural world.”
You can follow SUBJECT in Facebook, x and instagramor sign up here to receive our weekly newsletter.
