↓ Skip to main content

Polar bears experience skeletal muscle atrophy in response to food deprivation and reduced activity in winter and summer

Overview of attention for article published in Conservation Physiology, August 2017
Altmetric Badge

About this Attention Score

  • In the top 5% of all research outputs scored by Altmetric
  • High Attention Score compared to outputs of the same age (92nd percentile)
  • High Attention Score compared to outputs of the same age and source (80th percentile)

Mentioned by

blogs
1 blog
twitter
38 tweeters

Citations

dimensions_citation
12 Dimensions

Readers on

mendeley
49 Mendeley
You are seeing a free-to-access but limited selection of the activity Altmetric has collected about this research output. Click here to find out more.
Title
Polar bears experience skeletal muscle atrophy in response to food deprivation and reduced activity in winter and summer
Published in
Conservation Physiology, August 2017
DOI 10.1093/conphys/cox049
Pubmed ID
Authors

John P. Whiteman, Henry J. Harlow, George M. Durner, Eric V. Regehr, Bryan C. Rourke, Manuel Robles, Steven C. Amstrup, Merav Ben-David

Abstract

When reducing activity and using stored energy during seasonal food shortages, animals risk degradation of skeletal muscles, although some species avoid or minimize the resulting atrophy while experiencing these conditions during hibernation. Polar bears may be food deprived and relatively inactive during winter (when pregnant females hibernate and hunting success declines for other demographic groups) as well as summer (when sea ice retreats from key foraging habitats). We investigated muscle atrophy in samples of biceps femoris collected from free-ranging polar bears in the Southern Beaufort Sea (SBS) throughout their annual cycle. Atrophy was most pronounced in April-May as a result of food deprivation during the previous winter, with muscles exhibiting reduced protein concentration, increased water content, and lower creatine kinase mRNA. These animals increased feeding and activity in spring (when seal prey becomes more available), initiating a period of muscle recovery. During the following ice melt of late summer, ~30% of SBS bears abandon retreating sea ice for land; in August, these 'shore' bears exhibited no muscle atrophy, indicating that they had fully recovered from winter food deprivation. These individuals subsequently scavenged whale carcasses deposited by humans and by October, had retained good muscle condition. In contrast, ~70% of SBS bears follow the ice north in late summer, into deep water with less prey. These 'ice' bears fast; by October, they exhibited muscle protein loss and rapid changes in myosin heavy-chain isoforms in response to reduced activity. These findings indicate that, unlike other bears during winter hibernation, polar bears without food in summer cannot mitigate atrophy. Consequently, prolonged summer fasting resulting from climate change-induced ice loss creates a risk of greater muscle atrophy and reduced abilities to travel and hunt.

Twitter Demographics

The data shown below were collected from the profiles of 38 tweeters who shared this research output. Click here to find out more about how the information was compiled.

Mendeley readers

The data shown below were compiled from readership statistics for 49 Mendeley readers of this research output. Click here to see the associated Mendeley record.

Geographical breakdown

Country Count As %
Unknown 49 100%

Demographic breakdown

Readers by professional status Count As %
Student > Bachelor 9 18%
Researcher 9 18%
Student > Ph. D. Student 8 16%
Student > Master 7 14%
Professor 2 4%
Other 4 8%
Unknown 10 20%
Readers by discipline Count As %
Agricultural and Biological Sciences 17 35%
Environmental Science 5 10%
Biochemistry, Genetics and Molecular Biology 3 6%
Neuroscience 3 6%
Nursing and Health Professions 3 6%
Other 5 10%
Unknown 13 27%

Attention Score in Context

This research output has an Altmetric Attention Score of 31. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 29 September 2019.
All research outputs
#981,504
of 21,190,873 outputs
Outputs from Conservation Physiology
#63
of 627 outputs
Outputs of similar age
#22,468
of 289,172 outputs
Outputs of similar age from Conservation Physiology
#2
of 5 outputs
Altmetric has tracked 21,190,873 research outputs across all sources so far. Compared to these this one has done particularly well and is in the 95th percentile: it's in the top 5% of all research outputs ever tracked by Altmetric.
So far Altmetric has tracked 627 research outputs from this source. They typically receive a lot more attention than average, with a mean Attention Score of 14.5. This one has done particularly well, scoring higher than 90% of its peers.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 289,172 tracked outputs that were published within six weeks on either side of this one in any source. This one has done particularly well, scoring higher than 92% of its contemporaries.
We're also able to compare this research output to 5 others from the same source and published within six weeks on either side of this one. This one has scored higher than 3 of them.