The BRICS TimesScavenger species risk losing a key food supply as polar bear numbers fall.
Polar Bears Feed the Arctic Ecosystem
One polar bear can leave about 300 kilograms of prey for other animals yearly. Researchers estimate these meat-eaters provide 7.6 million kilograms of leftover food. This is for scavengers across the entire Arctic. This data was reported in the journal Oikos on October 28. It highlights the vital role these apex predators play. They feed many species in this vast region. Climate change is warming the Arctic, endangering polar bear populations. These findings show how the food web might be badly shaken.
Leftovers are a Crucial Biomass
Scientists already knew polar bears mainly eat the fat or blubber of their prey. The prey is usually seals, and the bears leave the rest of the body. Nicholas Pilfold worked in the Arctic for 15 years. This San Diego Zoo Wildlife Alliance scientist noted the leftovers’ importance was overlooked. Pilfold and his team studied scavenging reports and observations. These records of activity around carcasses went back to the 1930s. The team also analyzed seal calorie counts and bear consumption rates.
Millions of Kilograms of Carrion
During peak hunting season, a polar bear kills one seal every 3 to 5 days. These are typically ringed seals. This equates to about 1,000 kilograms of food each year. A bear eats most of the mass. It leaves roughly 30 percent available for others. The Arctic has an estimated 26,000 polar bears. All these leftovers create millions of kilograms of scavenger food. This includes arctic foxes, gulls, and ravens. Other polar bears also benefit from this carrion. Wolves, snowy owls, and grizzly bears sometimes feast on the remains. Study coauthor Holly Gamblin works at the University of Manitoba. She states other species could not access this food otherwise.
Impact of a Warming Arctic
Pilfold has seen these interactions directly. Foxes often follow the bear’s tracks, waiting for the abandoned meat. Birds also circle above and patiently await their opportunity. Expert Jon Aars finds these findings unsurprising. This food source is likely “rather important” for other species, he says. This is especially true when other food is hard to find. However, the Arctic is rapidly warming. This harms polar bear populations and reduces their leftovers. Pilfold warns that declining bear numbers mean less carrion biomass.
Losing a Vital Resource
Two regions show declining polar bear sub-populations. The team calculates an estimated 323,000 kilograms of carrion is already lost there yearly. Melting ice might also make the leftovers harder for scavengers to reach. Aars notes that predicting the exact impact of this decrease is difficult. However, he confirms it will have a serious impact. This effect will vary across species and parts of the Arctic.
