Enlarge /. Gosh what big teeth do you have?
Reindeer herders on the Siberian island of Bolshoy Lyakhovsky recently stumbled upon the frozen carcass of a cave bear. Nearby, on the Siberian mainland of Yakutia, a tiny, beautifully preserved cave bear cub recently emerged from another patch of melting permafrost. It is the first time in 15,000 years that humans have encountered a cave bear in the flesh – until now we only know the species from bones, tracks and abandoned nests.
The bear necessities
Many of our ancestors knew cave bears (Ursus spelaeus) only too well. In the Denisova Cave in the Siberian Altai Mountains, about 3,600 km from Bolshoi Lyakhovsky Island, a 2019 study of coprolites (fossil poop) and ancient DNA mixed into the cave sediment found bears every now and then had lived in the cave for 300,000 years, probably alternating with the Neanderthals, Denisovans and Homo sapiens, who also lived there at different times.
In fact, most of the cave bear fossils have been found in caves, and paleontologists believe these bears likely lived in the caves all day instead of just taking a short four month nap. Across Europe and Asia, bears and humans have likely fought over the same property for around 300,000 years. It probably wasn't a big competition, however. These clumsy Ice Age giants stood 3.5 meters tall when they straightened on their hind legs, and the largest males weighed up to 600 kilograms. That's about the size of a large polar bear or Kodiak bear today. You wouldn't want to meet anyone in a dark cave.
But a group of reindeer herders on Bolshoy Lyakhovsky met in broad daylight thanks to a patch of melting permafrost. It must still have been a breathtaking moment. The Bolshoi Lyakhovsky bear and Yakutia cub have been basically anoxic, frozen state for the past 22,000 to 40,000 years, and their muscles, skin, fur, and organs are well preserved except for the tips of their noses. That said, we can see what a full-fleshed, furry cave bear actually looked like, but it's also a treasure trove of information about each bear's eating habits, health, microbiome, and much more.
"We need to examine the bear's carcass using all modern scientific research methods – molecular genetic, cellular, microbiological and others," Northeastern Federal University molecular paleontologist Lena Grigorieva told the Siberian Times. "The research is planned on as large a scale as the study of the famous Malolyakhovsy mammoth." One of the first tasks will be radiocarbon dating of the remains to accurately estimate the age of the bears.
The people who found the bear gave it to Northeastern Federal University in Yakutsk, where Grigorieva and her colleagues studied other extinct Pleistocene megafauna such as mammoths and woolly rhinos.
The carcass is a little mushy, but we can all only hope to look this good after at least 20,000 years.
Note to researchers: Please do the science snoot.
Gosh what big teeth do you have?
The juvenile was found on the mainland and is likely around 39,000 years old.
An unbearable situation
Everywhere in the Arctic, the warming climate is melting tens of thousands of years of permafrost, creating a long-dead megafauna. Humans have discovered the intact remains of mammoths, woolly rhinos, wolf pups and cave lion cubs in recent years. Archaeologists and paleontologists in many areas are now racing against the clock to dig up and preserve the artifacts and animal remains exposed by melting permafrost and glaciers. The same frozen ground or sheets of ice that have hidden these objects from view for millennia have also preserved them. Once exposed, they quickly decay and take their secrets with them.
The melting permafrost also reveals buried animal carcasses that long-dormant bacteria can bring back to an unprepared world. And when the permafrost melts, it releases more carbon into the atmosphere, accelerating the warming process that caused the problem in the first place.
Finds like the Bolshoi Lyakhovsky bear can actually help ecologists to mitigate some of the damage. Several studies in recent years suggest that massive herbivores such as mammoths and woolly rhinos acted as "ecosystem engineers" to conserve the grassland steppes in the Pleistocene tundra and protect the permafrost that is now melting across much of the Arctic. According to geophysicist and ecologist Sergey Zimov and his colleagues, the animals' heavy steps compacted the permafrost in winter and kept it frozen hard enough to better withstand the summer melt cycle.
Zimov and his colleagues have released large herbivores such as bison to a nature reserve in Yakutia in recent years to test the hypothesis. So far, they haven't mentioned any plans to add large bears to the mix.