Nursing behavior of wild polar bears in the Canadian High Arctic

• Published in: Canadian Journal of Zoology
• Main Authors: Stirling, Ian, Burns, Lynne E., Regehr, Eric V., Laidre, Kristin L., Spencer, Cheryl
• Other Authors: Environment and Climate Change Canada, University of Alberta, Natural Sciences and Engineering Research Council of Canada, Northwest Territories Department of Environment and Natural Resources, Nunavut Wildlife Management Board, Polar Bears International
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2024
• Subjects: Nunavut; Radstock Bay; Ursus maritimus
• Online Access: http://dx.doi.org/10.1139/cjz-2024-0001; https://cdnsciencepub.com/doi/full-xml/10.1139/cjz-2024-0001; https://cdnsciencepub.com/doi/pdf/10.1139/cjz-2024-0001

During 17 spring and summer field seasons between 1973 and 1999, we documented 220 bouts of nursing by dependent polar bear ( Ursus maritimus Phipps, 1774) cubs at Radstock Bay, Nunavut, Canada. The overall mean duration of nursing bouts for cubs-of-the-year (COY) and yearlings (YRLG) litters was 7.1 min (standard deviation (SD) = 3.3, range = 1–23). Mean nursing bout durations of one- and two-cub litters of COY and YRLG in spring and summer seasons ranged from 6.09 to 7.78 min and from 5.00 to 9.18 min, respectively. The overall mean duration of inter-nursing intervals for COY and YRLG litters was 5.7 h (SD = 4.9, range = 0.0–35.0). The mean inter-nursing interval for one-cub litters was 6.4 h (SD = 4.6, range = 0.0–20.2) and for two-cub litters was 5.1 h (SD = 5.1, range = 0.0–35.0). We found no evidence for effects of season or cub age class on nursing behavior. We found weak evidence that two-cub litters nurse slightly longer than one-cub litters, potentially reflecting reduced nursing efficiency due to sibling rivalry. There was neither evidence for diel patterns in nursing behavior nor a detectable relationship between the cessation of nursing and the onset of hunting or sleeping by the adult female.