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High-energy, high-fat lifestyle challenges an Arctic apex predator, the polar bear

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Science  02 Feb 2018:
Vol. 359, Issue 6375, pp. 568-572
DOI: 10.1126/science.aan8677
  • Fig. 1 Field movements and accelerometer signatures of polar bears in April 2014 to 2016.

    (A) Capture and recapture locations and GPS movement paths of nine female polar bears dosed with DLW and equipped with GPS-equipped video camera collars and archival loggers with triaxial accelerometers and conductivity sensors. Gray area denotes land; white area shows sea ice cover. (Inset) Orientation of the accelerometer while attached to the video collar. (B) Accelerometer signatures of static acceleration in the surge (x), heave (y), and sway (z) directions and overall dynamic body acceleration (ODBA) while walking, swimming, and standing. Images show the corresponding behaviors derived from the animal-borne video camera.

  • Fig. 2 Relationship between body mass and RMR in polar bears and other ursids.

    RMR of an adult female polar bear (orange triangle, this study), compared with mean RMRs of subadult polar bears (orange circle), hibernating adult female polar bears (orange square), hibernating adult male brown bears (blue square), black bears (black circle), hibernating black bears (black square), adult and subadult panda bears (green circle), and female sloth bears (purple circle). Sources are available in the supplementary materials. The dashed line is the allometric regression for RMR in vertebrate-eating carnivores (20). The solid line is the allometric regression for RMR in eutherian mammals (21). (Inset) The adult female bear resting in the metabolic chamber from the present study.

  • Fig. 3 Daily FMR and overall FMR in relation to body mass, movement, and activity rate of polar bears.

    (A) Mean daily FMRs of female polar bears on the sea ice in relation to body mass. The allometric regression (solid line) is compared with predicted daily FMRs for marine and terrestrial mammalian carnivores (upper dashed line) (26), and predicted daily RMRs (lower dotted line) (21). (B) Least squares regression (solid line) of mean daily mass-specific FMR in comparison with mean movement rate. (C) Least squares regression (solid line) of mean daily mass-specific FMR in comparison with mean activity rate derived from video collars. (D) Least squares regression (solid line) of overall mass-specific FMR in comparison with total distance moved over 8 to 11 days. Regression statistics are provided in the main text. Each point represents a single value for one bear in (A) to (D).

  • Fig. 4 Feeding demands, changes in body mass, and foraging success of polar bears.

    (A) Number of ringed seals required for a female polar bear to meet its energy demands over 10 to 12 days on the spring sea ice based on our greatest energy expenditure, mean (±SE) energy expenditure, and lowest energy expenditure. (B) Changes in body mass, lean body mass, and fat mass of female polar bears on the sea ice over 8 to 11 days. Measures of changes in lean body mass and fat mass were only available for bears five to nine (19). Bar heights represent data for individual bears. (C) Image of a polar bear eating a recently killed ringed seal. (D) Prey type consumed by female polar bears. Bar heights represent data for individual bears.

    PHOTOS: NOAA

Supplementary Materials

  • High-energy, high-fat lifestyle challenges an Arctic apex predator, the polar bear

    A. M. Pagano, G. M. Durner, K. D. Rode, T. C. Atwood, S. N. Atkinson, E. Peacock, D. P. Costa, M. A. Owen, T. M. Williams

    Materials/Methods, Supplementary Text, Tables, Figures, and/or References

    Download Supplement
    • Materials and Methods
    • Figs. S1 to S3
    • Tables S1 to S2
    • References

    Images, Video, and Other Media

    Movie S1
    Video from a camera collar on a polar bear (bear #1) while on the sea ice of the Beaufort Sea in April 2014. This video shows an adult female polar bear on April 9, 2014 digging a hole in the sea ice potentially to entice a seal to come up to breath as she proceeds to still-hunt at this location and then pounces through the ice into the water. The video shows her on April 10, 2014 walking on the sea ice and on April 11, 2014 moving a recently caught ringed seal. The video shows her on April 12, 2014 interacting with an adult male polar bear.
    Movie S2
    Video from a camera collar on a polar bear (bear #4) while on the sea ice of the Beaufort Sea in April 2015. This video shows an adult female polar bear on April 16, 2014 swimming under the sea ice. The video shows her on April 18, 2014 still-hunting and pouncing through the ice into the water. On April 19, 2014, the video shows her still hunting and pouncing through the ice into the water at another location.
    Movie S3
    Video from a camera collar on a polar bear (bear #5) while on the sea ice of the Beaufort Sea in April 2015. This video shows an adult female polar bear on April 12, 2015 eating the muscle from the remains of an old seal carcass. Later on the same day, she is shown walking on the sea ice.
    Movie S4
    Video from a camera collar on a polar bear (bear #8) while on the sea ice of the Beaufort Sea in April 2016. This video shows an adult female polar bear on April 10, 2016 catching and eating a ringed seal. The video shows her on April 12, 2016 stalking, running at, and attempting to catch a bearded seal.

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