Post-Den Emergence Behavior of Polar Bears (Ursus maritimus) in Northern Alaska

• Published in: ARCTIC
• Main Authors: Smith, Tom S., Partridge, Steven T., Amstrup, Steven C., Schliebe, Scott
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Arctic Institute of North America 2009
• Subjects: Alaska; behavior; den emergence; maternity den; North Slope; polar bear; Ursus maritimus; comportement; sortie de la tanière; tanière de maternité; versant nord; ours polaire; Arctic; north slope
• Online Access: https://journalhosting.ucalgary.ca/index.php/arctic/article/view/63305

We observed polar bear (Ursus maritimus) maternity den sites on Alaska’s North Slope in March 2002 and 2003 in an effort to describe bears’ post-den emergence behavior. During 40 sessions spanning 459 h, we observed 8 adults and 14 dependent cubs outside dens for 37.5 h (8.2% of total observation time). There was no significant difference between den emergence dates in 2002 (mean = 15 Mar ± 4.1 d) and 2003 (mean = 21 Mar ± 2.1 d). Following initial den breakout, polar bears remained at their den sites for 1.5 to 14 days (mean = 8.1 ± 5.1 d). The average length of stay in dens between emergent periods was significantly shorter in 2002 (1.79 h) than in 2003 (4.82 h). While outside, adult bears were inactive 49.5% of the time, whereas cubs were inactive 13.4% of the time. We found no significant relationships between den emergence activity and weather. Adult polar bears at den sites subjected to industrial activity exhibited significantly fewer bouts of vigilance than denned bears in undisturbed areas (t = -5.5164, df = 4, p = 0.00). However, the duration of vigilance behaviors at sites near industrial activity was not significantly shorter than at the other sites studied (t = -1.8902, df = 4, p = 0.07). Results for these bears were within the range of findings in other studies of denned polar bears. Nous avons observé des tanières de maternité d’ours polaires (Ursus maritimus) sur le versant nord de l’Alaska aux mois de mars 2002 et 2003 dans le but de décrire le comportement de sortie des ours après leur séjour dans la tanière. Dans le cadre de 40 séances d’observation ayant duré 459 heures, nous avons observé 8 ours adultes et 14 oursons à charge en dehors des tanières pendant 37,5 heures (soit 8,2 % de la durée d’observation totale). Il n’y avait pas de différence importante entre les dates de sortie des tanières en 2002 (moyenne = 15 mars ± 4,1 j) et 2003 (moyenne = 21 mars ± 2,1 j). Après la première sortie de la tanière, les ours polaires restaient à l’emplacement de leur tanière pendant 1,5 à 14 jours ...