The final surviving member of a species—the person whose dying brings extinction—is known as an endling. These people can typically be recognized, even named. Many extra of them stay and die unseen. For instance, archaeological proof reveals that the woolly mammoth endling lived about 4,000 years in the past on Wrangel Island, 87 miles off the coast of Siberia. Mammoths survived there for millennia after the remainder of their type have been worn out by altering local weather and human hunters. However ultimately, via some mixture of things, together with excessive climate occasions and dangerous mutations acquired via heavy inbreeding, additionally they perished. I thought of them as I listened to Kristin Laidre speaking about polar bears.
Laidre, who’s an ecologist on the College of Washington, has recognized a singular group of polar bears that lives in Greenland’s southeastern tip. Genetically remoted from different populations, the bears’ habits make them much less depending on sea ice—the floating, frozen platforms on which most polar bears hunt, journey, and lift their younger. As sea ice disappears, so do the polar bears’ odds of survival. These in Southeast Greenland appear higher suited to a warming world, and will persist whereas the remainder of the Arctic turns into uninhabitable.
“Does this imply polar bears are saved?” Laidre instructed me. “It doesn’t.” Just like the Wrangel mammoths, they could outlast others of their type, however they received’t maintain out perpetually. Maybe Southeast Greenland is just the place the place the polar-bear endling will stay out its species’ remaining days.
About 26,000 polar bears are left within the wild, divided into 19 subpopulations that stay in several corners of the Arctic. One in all these subpopulations lives alongside 2,000 miles of principally uninhabited shoreline in East Greenland, and had by no means been correctly studied. In 2011, Laidre and her colleagues started a decade-long effort to rely these bears so the Greenland authorities might set conservation objectives and subsistence-hunting quotas. Following talks with native subsistence hunters, the crew started systematically working its approach alongside the coast.
The researchers hit Southeast Greenland in 2015, principally to be thorough. A really quick present rips down Greenland’s jap flank, filling the southeast with small and sparsely packed ice floes—“a troublesome panorama for a polar bear to make use of,” Laidre instructed me. She and her colleagues guessed that some bears would possibly stay within the area’s fjords, however “I keep in mind flying into one and anticipating to not see very a lot,” Laidre stated. “Inside 10 minutes, we noticed six bears all inside a couple of kilometers of one another.” On a standard bear-spotting flight, she’d anticipate to see one each hour or so. What have been so many polar bears doing in a spot that must be principally bear-free?
That first journey was short-lived, however Laidre knew she had to return, regardless that Southeast Greenland has unstable climate, a harsh shoreline, nearly no human settlements, and no spots for gas or meals. To work there, the researchers buried barrels of gas alongside the snowy shoreline, creating makeshift depots {that a} helicopter might hopscotch between. Once they discovered polar bears, they’d tranquilize them from the transferring helicopter, accumulate bodily measurements and tissue samples, and (if the bear was an grownup feminine) match a monitoring collar.
Normally, the crew commuted from a base two hours away. However one night, the scientists determined to sleep in an deserted mining camp, with the intention of beginning the subsequent day nearer the animals. They received their want: That evening, Laidre heard the sound of enormous paws treading on squeaky snow, and woke to seek out … a polar bear working off along with her bag of polar-bear-tissue samples. She exited the camp, pursuing the bear whereas banging a steel spoon in opposition to a frying pan. It dropped the dear bag and fled. “Then we realized it additionally had taken a couple of bites of our helicopter,” she instructed me.
From the hard-won information, the crew realized that “these are severely native bears,” Laidre stated. Though polar bears often roam over giant distances, these in Southeast Greenland keep in the identical fjord for years. Even after they unintentionally received caught within the speedy jap present and have been swept off to the south, they’d simply swim to shore and trundle again to the identical fjord they began from. Their homebody instincts are so sturdy that they by no means work together with bears that stay additional up the coast. It’s as if an invisible wall at 64 levels north separates the southeast bears from their northeast cousins.
The bears’ DNA instructed the identical story. “Polar bears are remarkably genetically related to one another,” Beth Shapiro, an evolutionary biologist at UC Santa Cruz, instructed me. However the Southeast Greenland bears are so distinct from the 19 identified subpopulations that when Shapiro’s crew first analyzed the samples that Laidre had collected, “we thought we’d performed one thing flawed,” she stated. These are essentially the most genetically remoted polar bears on this planet—a twentieth subpopulation that’s been principally self-contained in a nook of Greenland for a couple of hundred years, and probably longer.
Like all different polar bears, these in Southeast Greenland use sea ice as platforms from which they hunt seals. That ice is offered for less than about 100 days of the yr, which isn’t sufficient. However at different occasions, the bears can survive due to the weird panorama they inhabit: In lieu of sea ice, they use freshwater icebergs which are funneled into the fjord by a glacier. This “glacial mélange” is the key of their survival, not less than for now. In different components of the Arctic, polar bears would possibly take pleasure in nearly twice as many ice-covered days in a yr, however they’re nonetheless faring poorly “as a result of as soon as that ice is gone, they don’t have entry to an alternate,” Laidre stated.
The Southeast Greenland polar bears are “bears of the long run,” Laidre added. Because the Arctic warms, the variety of ice-free days will improve, and extra polar bears will expertise the identical circumstances that their Southeast Greenland counterparts at the moment face. Most received’t have a glacial backup, and can die. If carbon emissions proceed alongside their present course, almost all the subpopulations will doubtless be worn out by the top of this century. The Southeast Greenland subpopulation is “an instance of what could occur in a warming Arctic, because the bears persist in smaller teams in smaller areas on the fringes of their vary, and turn into progressively extra remoted, with growing inbreeding over time,” Andrew Derocher, a polar-bear researcher on the College of Alberta, instructed me.
“This shouldn’t be spun as ‘By some means, glaciers will save polar bears,’” Laidre stated. Most populations don’t have entry to glacier fronts, and apart from, glaciers “are in retreat primarily all over the place in Greenland,” John Whiteman, the chief analysis scientist at Polar Bears Worldwide, instructed me. That’s one cause “it’s extremely unlikely,” Derocher stated, that even the Southeast Greenland bears will “persist far into the long run with the warming that’s predicted.” There additionally aren’t sufficient of them to maintain a thriving inhabitants, and their delivery charges are already worryingly low. Inbreeding would possibly ultimately riddle them with genetic issues.
“I don’t suppose it’s completely hopeless for polar bears, however we’d like sturdy motion to restrict human-caused local weather change if we wish to save them,” Laidre stated. In any other case, the Southeast Greenland inhabitants could possibly be the fashionable equal of the Wrangel Island mammoths—the final survivors of a world that now not has a spot for them.
