How scientists attempt to weigh a number of the fattest bears on Earth

Bear 151, or “Walker,” is likely one of the yr’s contestants. Right here, fishing for salmon at Brooks Falls. (N. Boak / U.S. Nationwide Park Service/)

This week, anybody with web entry can assist to find out the winner of a weird competitors: which bear in Katmai Nationwide Park and Protect in Alaska is the fattest of all. Since 2013, the park and its associate organizations have held an internet competitors through which the general public can vote on who they assume is the heaviest ursine. “I wish to say we’ve gotten so massive that we’re rivaling shark week,” says Sara Wolman, a challenge supervisor on the Katmai Conservancy, a nonprofit group that helps the preservation of Katmai Nationwide Park.

Proper now, the brown bears that dwell in Katmai (they quantity some 2,200) are ingesting all of the salmon and berries they will eat earlier than the winter arrives, bringing with it a pointy decline within the meals out there and forcing the animals into hibernation. By images and a dwell digital camera positioned in Brooks Falls, the place these bears hunt for salmon, individuals can vote for who they assume is the chubbiest of all of them.

However as everyone knows, cameras will be deceitful. And really measuring the bears to get a extra goal ranking can be difficult, too. Sometimes, an ecologist who needs to precisely measure a bear’s weight must seize it to take action. “The bears should be darted with tranquilizers oftentimes from helicopters, as an illustration, or they should be trapped in a culvert. It’s type of an intrusion on their lives,” says Mike Fitz, a nature specialist at, a multimedia group that hosts the voting platform for Fats Bear Week.

Bear 128, or

Bear 128, or “Grazer.” (Courtesy U.S. Nationwide Park Service/)

However for the non-scientific functions of the competitors, there’s no must seize the bears and weigh them—that will be extremely pointless. In 2019, a workforce of Katmai officers examined a brand new means to determine how fats the contestants are. And their concept could possibly be a place to begin in the direction of a brand new technique of non-invasive, weight-measuring instruments.

Final yr, utilizing laser scanning, biologists and geographic info specialists at Katmai Park measured 5 bears with out capturing, sedating, or manipulating them, and so they did the identical this yr. Even when questions stay concerning the new instrument, it might change the best way biologists measure bear weight, which is essential to figuring out a inhabitants’s well being.

Using this new expertise wasn’t deliberate. In accordance with Wolman and Fitz, geographic info specialist Joel Cusick and a few of his colleagues have been close to Brooks Falls measuring buildings and different infrastructure for Alaska’s regional workplace of the Nationwide Park Service. To do it, that they had a Trimble SX10 scanner, a instrument that measures objects like buildings or the topography of a panorama. It emits laser beams that bounce again to the gadget after they attain an object. Later, particular software program processes all the information factors and creates a three-dimensional mannequin of the captured object.

The team processed the information by digitally removing rocks and plants from the images, and found the volume of the bear’s bodies.

The workforce processed the data by digitally eradicating rocks and crops from the photographs, and located the amount of the bear’s our bodies. (J. Cusick / NPS./)

Led by Cusick, they determined to go to the wildlife viewing platform at Brooks Falls, positioned only a few yards from the sting of the river, Fitz says. The platform permits anybody visiting the park in late summer time and early fall to witness the spectacle of brown bears fishing for salmon, whose migration is slowed down by the waterfalls. Cusick and the workforce needed to look forward to bears to face nonetheless for a minimum of 16 seconds. Over a day, they managed to seize sufficient details about 5 bears. Their names are 32 Chunk, 151 Walker, 480 Otis, 747, and 854 Divot, in line with a weblog publish Fitz wrote concerning the course of.

They then processed the data by digitally eradicating rocks and crops from the photographs, and located the amount of the bear’s our bodies (a special metric than their weight). The toughest half, says Fitz, was calculating the animal’s mass. Because the scanner doesn’t present details about the inner composition of the bears, the workforce needed to approximate the chances of physique fats, muscle, and water of the scanned animals. The winner from the small pattern was a bear referred to as 747: he weighed an estimated 1,408 lb. The lightest one, a bear referred to as 854 Divot, weighed a mere 676 lb.

These numbers affirm what is thought amongst bear biologists: the bears residing within the Katmai space are in all probability the largest brown bears on Earth. Like some other bear, these animals enter a part referred to as hyperphagia throughout late summer time. Their our bodies develop into immune to leptin, the hormone that fats reserves produce when an animal has a full abdomen. However in contrast to different bears in different areas, the huge ursines at Katamai’s Brooks Falls have entry to all types of meals. They will gorge on berries and different crops that give them fast, sugary vitality and the tons of salmon passing by way of Brooks Falls. “That’s a extremely, actually particular situation that doesn’t occur that usually,” says Pleasure Erlenbach, a bear biologist with the U.S. Fish and Wildlife Service. “So the bears of Brooks Falls are extra the exception than the norm.”

Erlenbach, who labored at Katmai till 2017, discovered that the inhabitants of bears residing in Katmai’s coastal space have a really completely different weight loss plan from these at Brooks Falls: even when the coastal bears are close to otters and seals, they’re vegetarians for many of the yr. “From observing the bears at Brooks Falls, I can say with confidence that these bears are far, far larger than something you’d see on the coast,” she provides.

The load of bears can be essential for figuring out the well being of a inhabitants, says Erlenbach. “[Even] Should you don’t know the rest concerning the inhabitants, if you happen to’re ready to take a look at how fats the bears are and decide their percentages of physique fats, you’ll be able to infer how profitable they is likely to be having cubs,” she explains. (That’s as a result of even when bears breed throughout the summer time, a feminine bear can solely efficiently get pregnant if her physique fats share is excessive sufficient, and the milk she later produces can have a better share of fats, too, which is sweet for the cubs.)

Bear 747 in July 2019, at the beginning of the salmon season in Katmai.

Bear 747 in July 2019, originally of the salmon season in Katmai. (Courtesy U.S. Nationwide Park Service/)

Bear 747 weighed an estimated 1,408 lb in September 2019.

Bear 747 weighed an estimated 1,408 lb in September 2019. (Courtesy U.S. Nationwide Park Service/)

For now, the laser-scanning tech solely serves to fulfill the workforce’s curiosity about the true dimension of the fats bears of Katmai, says Fitz. Nevertheless, he believes sooner or later they might use it yearly to see if there’s a correlation between the burden of every animal and metrics like salmon numbers or particular person bear fishing success.

However there’s nonetheless a great distance till that turns into a actuality. First, they should use it in a situation the place they will measure a bear with out utilizing the brand new expertise, like with an animal in captivity. Then, they’ll should shoot the laser on the bears and work out the way to get the laser values to align with the opposite metrics they’ve obtained through a special technique, says Erlenbach. And after that, they’ll have to regulate their mannequin to the wild animals, because it’s unimaginable to seek out captive animals as massive as these in Katmai.

“The bears at Brooks camp are actually wholesome and actually fats, and so they make nationwide information, however that’s not the case for bears in every single place,” says Erlenbach. “Bears that don’t have a Bristol Bay Sockeye salmon run and a pristine ecosystem should not experiencing these situations. These bears are undoubtedly the fortunate ones.”

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