Midsummer observations on the behavior of wild polar bears ( Ursus maritimus)

• Published in: Canadian Journal of Zoology
• Main Author: Stirling, Ian
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1974
• Subjects: Caswall Tower; Devon Island; Patience; Phoca hispida; Ursus maritimus
• Online Access: http://dx.doi.org/10.1139/z74-157; http://www.nrcresearchpress.com/doi/pdf/10.1139/z74-157

Wild polar bears (Ursus maritimus) were observed from Caswall Tower, Devon Island (74°43′ N; 91°10′ W), from 24 July to 8 August 1973. A total of 602.7 bear hours of observations was recorded. Two types of hunting were observed, stalking and still-hunting. Of 288 hunts observed, 65 (22.6%) were stalks and 233 (77.4%) were still-hunts. All cubs observed hunted, but they exhibited great variety in patience and apparent skill. Scavenging and intraspecific competition for possession of kills were observed. When threatened, adult females with cubs were not subordinate to tears of any other age or sex classes. A diurnal rhythm was recorded in which bears slept most during the latter third of the 24-h cycle and least in the first third. The average of 17 sleeps longer than 60 min was 465 ± 301.3 min.Basking ringed seals (Phoca hispida) alternated between lying flat and raising their heads to look about for predators. The mean duration of the lying and looking phases was 26.3 and 7.0 s respectively (n = 591 and 580). The variation between individual seals was greater than within individuals. If a group of seals hauled out together, all individuals maintained watchful behavior; no single animal acted as a "sentry" for the others.