Enlarge / Portion of a reproduction of cave paintings in France, showing rhinos (among other species). (credit: JEFF PACHOUD)

For most people, an extinct species is an abstraction, a set of bones they might have seen on display in a museum. For Gennady Boeskorov, they are things he has interacted with directly, studying their fur, their skin, their internal organs—experiencing these animals much as they existed thousands of years ago. Some of the well-preserved Pleistocene animals he has worked with include the mummified remains of woolly mammoths (Mammuthus primigenius), an extinct form of rabbit (Lepus tanaiticus), and cave lion cubs (Panthera spelaea).

His latest paper also makes it clear that woolly rhinoceroses belong on this list. Boeskorov is a senior researcher at the Diamond and Precious Metals Geology Institute, Siberian Branch of the Russian Academy of Sciences, as well as a professor at the North-Eastern Federal University in Yakutsk. This July, he and his colleagues described the relatively recent discovery of three woolly rhinoceros mummies, one of which is new to science, in a paper published in the journal Doklady Earth Sciences.

Woolly rhinos (Coelodonta antiquitatis) were stocky, long-haired, two-horned denizens that inhabited Eurasia during the Pleistocene, a period that includes the most recent glacial expansion. They coexisted with woolly mammoths, placing second on the list of largest animals in this ecosystem (behind their tusked proboscidean coevals), and shared a similar dense coat of hair to protect against the cold.

Enlarge / Interior view of the Rhino Barn. Exposed fossil skeletons left in-situ for research and public viewing. (credit: Rick E. Otto, University of Nebraska State Museum)

Death was everywhere. Animal corpses littered the landscape and were mired in the local waterhole as ash swept around everything in its path. For some, death happened quickly; for others, it was slow and painful.

This was the scene in the aftermath of a supervolcanic eruption in Idaho, approximately 1,600 kilometers (900 miles) away. It was an eruption so powerful that it obliterated the volcano itself, leaving a crater 80 kilometers (50 miles) wide and spewing clouds of ash that the wind carried over long distances, killing almost everything that inhaled it. This was particularly true here, in this location in Nebraska, where animals large and small succumbed to the eruption’s deadly emissions.

Eventually, all traces of this horrific event were buried; life continued, evolved, and changed. That's why, millions of years later in the summer of 1971, Michael Voorhies was able to enjoy another delightful day of exploring.

Enlarge / An artist's conception of one of the last mammoths of Wrangel Island. (credit: Beth Zaiken)

A small group of woolly mammoths became trapped on Wrangel Island around 10,000 years ago when rising sea levels separated the island from mainland Siberia. Small, isolated populations of animals lead to inbreeding and genetic defects, and it has long been thought that the Wrangel Island mammoths ultimately succumbed to this problem about 4,000 years ago.

A paper in Cell on Thursday, however, compared 50,000 years of genomes from mainland and isolated Wrangel Island mammoths and found that this was not the case. What the authors of the paper discovered not only challenges our understanding of this isolated group of mammoths and the evolution of small populations, it also has important implications for conservation efforts today.

A severe bottleneck

It’s the culmination of years of genetic sequencing by members of the international team behind this new paper. They studied 21 mammoth genomes—13 of which were newly sequenced by lead author Marianne Dehasque; others had been sequenced years prior by co-authors Patrícia Pečnerová, Foteini Kanellidou, and Héloïse Muller. The genomes were obtained from Siberian woolly mammoths (Mammuthus primigenius), both from the mainland and the island before and after it became isolated. The oldest genome was from a female Siberian mammoth who died about 52,300 years ago. The youngest were from Wrangel Island male mammoths who perished right around the time the last of these mammoths died out (one of them died just 4,333 years ago).

Enlarge / Upper left: a reconstruction of Diadcetes Below: false color images of its foot and tail prints. Right: the section of the tail that left the print. (credit: Voigt et. al./Urweltmuseum GEOSKOP.)

Their feet left copious traces in muddy Permian floodplains, leaving tracks scattered across ancient sediments. But in one slab of such trackways, scientists uncovered something more: the trace of an animal’s tail as it dragged across the ground. Strikingly, these tail prints come complete with scale impressions—at 300 million years old, they’re among the earliest scale impressions we have.

This may seem small, but it shows us that some of the hardened skin structures necessary for our ancestors to survive on land had evolved much earlier than previously suspected. A paper published in Biology Letters this past May describes this discovery in detail.

A rare find

The particular slab holding these traces was discovered in 2020 at the Piaskowiec Czerwony quarry in Poland. Mining had stopped to enable paleontologists to search the red sandstone rocks for fossils. Gabriela Calábková described climbing upon “a huge pile of rubble” only to discover a sizable slab of fossil tracks at the very top. There, among one set of footprints, was something new.