Polar bears are at risk of starvation if the Arctic summer lasts too long

Polar bears are at risk of starvation if the Arctic summer lasts too long

Polar bears are at risk of starvation if the Arctic summer lasts too longFacebook/Kirsten Langenberger

the Polar bones They are marine ice animals, however Arctic summer Longer and longer will force them to spend more time on land, where they are unlikely to be able to adapt to living for long periods, and will even be at risk of Starve to death

A study published in the journal Nature Communications on Tuesday followed 20 specimens, wearing collars equipped with cameras and GPS, for three weeks in the western region of Hudson Bay (Canada), where a warming climate is likely to affect bones at a faster rate than Other Arctic regions.

During the time they are on land, when there is no sea ice, polar seals, from which they derive most of their energy, are out of reach.

The study suggests that “bones do not have behavioral and energetic strategies they can use to avoid losing weight during the summer on land, and this will be greater when they spend longer periods there,” the lead author of the research told EFE. Anthony Pagano of the USGS Alaska Science Center.

There is not enough food on Earth

Although these animals “show remarkable resilience in their behavior, they are still at risk of dying” from starvation due to the expected decline in Arctic sea ice, because the work suggests that the food they obtain on land does not give them “enough Food” and stressed the energy needed to resist for a longer period before reaching a state of starvation.

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Previous research has shown that the ice-free period in western Hudson Bay increased by three weeks between 1979 and 2015. Bones now remain on shore for an average of 130 days, compared to 100 or 110 days before.

Depending on different greenhouse gas emissions scenarios, time spent at sea is likely to increase by between five and ten days per decade.

Since polar bears are forced to put their feet on the ground earlier, the period in which they normally gain most of the energy they need to survive is shortened, and it is expected that you will be more likely to see polar bears. “Hunger is increasing, especially among juveniles and females with cubs.”

The researchers weighed the bones before and after the observation period, for three weeks between August and September, in addition to measuring their energy consumption.

From falling to going swimming

The animals showed several strategies for conserving energy reserves, which were independent of age, sex, reproductive stage (including pregnant females) or initial lipid levels. Despite the different behaviours, 19 of the 20 animals lost “similar amounts of body mass”, an average of one kilogram per day.

Many adult males simply conserve energy, burning calories at a similar rate HibernationBut 70% still searched for terrestrial foods such as berries, grasses and bird carcasses. Some adult females spend up to 40% of their time searching for food, and although the food gave them some energy benefits, they had to expend more energy to reach it.

Three swam long distancesAt a depth of 175 kilometers in open water, two people found the carcasses of marine mammals that they could not feed while swimming or coming ashore. Only one became obese after finding a dead marine mammal on land.

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They are not brown bones

It is difficult to determine how long they can starve because it depends on size and body condition, although previous studies have estimated that adult males “They will starve to death if the summer fast is extended to 180 days.”

Polar bears “are very different from brown bears,” Charles Robbins of Washington State University said in a statement. They can exceed three meters in length and weigh more than 1,500 kilograms, compared to their land-dwelling relatives, which are two meters long and 800 kilograms.

To maintain this huge mass, polar bears, which are “not brown bears with white coats,” Robbins added, rely on… Energy-rich fats from seals, That fish best in ice. The next goal is to use these data to predict the effects of expected sea ice loss on the reproduction and survival of specific populations of polar bears in different parts of their range.

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