Do Wild Polar Bears (Ursus maritimus) Use Tools When Hunting Walruses (Odobenus rosmarus)?

Since the late 1700s, reports of polar bears (Ursus maritimus) using tools (i.e., pieces of ice or stones) to kill walruses (Odobenus rosmarus) have been passed on verbally to explorers and naturalists by their Inuit guides, based on local traditional ecological knowledge (TEK) as well as accounts of direct observations or interpretations of tracks in the snow made by the Inuit hunters who reported them. To assess the possibility that polar bears may occasionally use tools to hunt walruses in the wild, we summarize 1) observations described to early explorers and naturalists by Inuit hunters about polar bears using tools, 2) more recent documentation in the literature from Inuit hunters and scientists, and 3) recent observations of a polar bear in a zoo spontaneously using tools to access a novel food source. These observations and previously published experiments on brown bears (Ursus arctos) confirm that, in captivity, polar and brown bears are both capable of conceptualizing the use of a tool to obtain a food source that would otherwise not be accessible. Based on the information from all our sources, this may occasionally also have been the case in the wild. We suggest that possible tool use by polar bears in the wild is infrequent and mainly limited to hunting walruses because of their large size, difficulty to kill, and their possession of potentially lethal weapons for both their own defense and the direct attack of a predator. Depuis la fin des années 1700, des signalements d’ours polaires (Ursus maritimus) se servant d’outils (comme des morceaux de glace ou des pierres) pour tuer des morses (Odobenus rosmarus) ont été communiqués verbalement par des guides inuits à divers explorateurs et naturalistes. Les guides en question se fondaient sur les connaissances écologiques traditionnelles (CET) locales de même que sur les interprétations de traces dans la neige ou les récits d’observations directes des chasseurs inuits ayant fait les signalements. Pour évaluer la possibilité que les ours polaires puissent parfois se servir d’outils pour chasser les morses en milieu sauvage, nous résumons : 1) les observations décrites aux premiers explorateurs et naturalistes par les chasseurs inuits au sujet de l’utilisation d’outils par les ours polaires; 2) la documentation récente attribuable aux chasseurs inuits et aux scientifiques; et 3) les récentes observations de l’ours polaire d’un zoo se servant d’outils spontanément pour avoir accès à une nouvelle source de nourriture. Ces observations, alliées à des expériences publiées au sujet d’ours bruns (Ursus arctos), permettent de confirmer qu’en captivité, tant les ours bruns que les ours polaires sont capables de conceptualiser l’utilisation d’un outil pour se procurer de la nourriture qui ne serait autrement pas accessible. D’après les renseignements prélevés auprès de toutes nos sources, cela aurait aussi pu être occasionnellement le cas en milieu sauvage. Nous suggérons que l’utilisation possible d’outils par les ours polaires en milieu sauvage n’est pas fréquente et qu’elle est surtout limitée à la chasse au morse en raison de la grande taille de cette espèce, de la difficulté à l’abattre et des armes potentiellement mortelles qu’elle possède, tant pour se défendre que pour attaquer un prédateur directement.&nbsp

Beluga, Delphinapterus leucas, Distribution and Survey Effort in the Gulf of Alaska

Beluga, Delphinapterus leucas, distribution in the Gulf of Alaska and adjacent inside waters was examined through a review of surveys conducted as far back as 1936. Although beluga sightings have occurred on almost every marine mammal survey in northern Cook Inlet (over 20 surveys reported here), beluga sightings have been rare outside the inlet in the Gulf of Alaska. More than 150,000 km of dedicated survey effort in the Gulf of Alaska resulted in sightings of over 23,000 individual cetaceans, of which only 4 beluga sightings (5 individuals) occurred. In addition, nearly 100,000 individual cetaceans were reported in the Platforms of Opportunity database; yet, of these, only 5 sightings (39 individuals) were belugas. Furthermore, approximately 19 beluga sightings (>260 individuals), possibly including resightings, have been reported without information on effort or other cetacean sightings. Of the 28 sightings of belugas outside of Cook Inlet, 9 were near Kodiak Island, 10 were in or near Prince William Sound, 8 were in Yakutat Bay, and 1 anomalous sighting was well south of the Gulf. These sightings support archaeological and commercial harvest evidence indicating the only persistent group of belugas in the Gulf of Alaska occurs in Cook Inlet

Reactions of Narwhals, Monodon monoceros, to Killer Whale, Orcinus orca, Attacks in the Eastern Canadian Arctic

A Killer Whale attack on Narwhals was observed at Kakiak Point in Admiralty Inlet, Nunavut, Canada, in August 2005. Behavioral responses of both Narwhals and Killer Whales were documented by direct observation. Data collected from Narwhals instrumented with satellite-linked transmitters 5 days prior to the arrival of Killer Whales were used to examine changes in Narwhal movement patterns (e.g., dispersal and clumping) five days before the attack, during the attack, and five days after Killer Whales left the area. A minimum of four Narwhals were killed by 12-15 Killer Whales in a period of 6 hours. Narwhals showed a suite of behavioral changes in the immediate presence of Killer Whales including slow, quiet movements, travel close to the beach (<2 m from shore), use of very shallow water, and formation of tight groups at the surface. These behavioral changes are consistent with Inuit accounts of Killer Whale attacks on Narwhals. During the attack, Narwhals dispersed broadly, the groups were less clumped (standard deviation of inter-whale mean latitudes and longitudes), Narwhal space-use doubled from pre-attack home ranges of 347 km2 to 767 km2 (kernel 50% probability), and Narwhals shifted their distribution further south of the attack site. After the disappearance of Killer Whales, north-south dispersal of Narwhals contracted and was similar to pre-attack levels, total space use decreased slightly (599 km2), yet west-east dispersal remained high. Narwhals were distributed significantly (P < 0.001) more broadly offshore in areas not used before the occurrence of Killer Whales. In general, short-term reactions of Narwhals to Killer Whale presence were obvious; yet normal behavior (as observed from shore) resumed shortly after Killer Whales left the area. Long-term (five day) Narwhal behavioral responses included increased dispersal of Narwhal groups over large offshore areas. This is among the few reports of eyewitness Killer Whale attacks on Narwhals in the high Arctic and is the first time changes in Narwhal behavior have been documented in response to a predation event through the use of satellite telemetry

Using Visual Observations to Compare the Behavior of Previously Immobilized and Non-Immobilized Wild Polar Bears

During 17 field seasons between 1973 and 1999, we conducted a long-term study of the behavior of undisturbed wild polar bears in Radstock Bay, southwest Devon Island, Nunavut. In a subset of 11 seasons (6 spring and 5 summer) between 1975 and 1997, we used three different drug combinations to chemically immobilize a small number of adult and subadult polar bears on an opportunistic basis and applied a temporary dye mark so that individual bears could be visually reidentified. We then used multinomial logistic regression to compare the behavior of 35 previously immobilized bears of five different demographic classes (sex, age, and reproductive status) to the behavior of non-immobilized bears of the same demographic classes in the same years and seasons. During the first two days after immobilization, bears slept significantly more and spent less time hunting than did bears that had not been immobilized. However, previously immobilized bears returned to the same behavioral patterns and proportion of total time spent hunting as non-immobilized bears within two days and no further negative behavioral effects were detected in the following 21 d. We visually confirmed successful hunting by three adult bears within 0.4 to 2.1 d of being immobilized, all of which went on to make additional kills within the following 24 h. The return to normal behavior patterns, including the ability to hunt successfully, within 48 h of immobilization appears consistent with the hypothesis that polar bears do not experience longer-term behavioral effects following brief chemical immobilization for conservation and management purposes. Durant 17 saisons de recherche, entre 1973 et 1999, nous avons effectué l’étude à long terme du comportement d’ours polaires sauvages non perturbés à la baie Radstock, dans le sud-ouest de l’île Devon, au Nunavut. Dans un sous-ensemble de 11 saisons (six printemps et cinq étés) échelonnées de 1975 à 1997, nous avons utilisé trois combinaisons de drogues différentes pour immobiliser chimiquement un petit nombre d’ours polaires adultes et d’ours polaires immatures de manière opportuniste, puis nous avons appliqué une marque de colorant temporaire sur les ours afin de pouvoir les réidentifier individuellement. Ensuite, nous avons recouru à la régression logistique multinomiale pour comparer le comportement de 35 ours précédemment immobilisés faisant partie de cinq catégories démographiques différentes (sexe, âge et état reproducteur) au comportement d’ours non immobilisés faisant partie des mêmes catégories démographiques pour les mêmes années et les mêmes saisons. Au cours des deux premières journées suivant l’immobilisation, les ours dormaient beaucoup plus et consacraient moins de temps à la chasse que les ours qui n’avaient pas été immobilisés. Cependant, les ours qui avaient été immobilisés ont repris les mêmes habitudes de comportement et consacré le même temps à la chasse que les ours non immobilisés en dedans de deux jours, et aucun autre effet négatif sur leur comportement n’a été décelé au cours des 21 jours qui ont suivi. Nous avons eu la confirmation visuelle d’une chasse réussie par trois ours adultes dans la période de 0,4 à 2,1 jours suivant l’immobilisation, tous trois ayant réussi à faire d’autres prises dans les 24 heures qui ont suivi. Le retour aux habitudes de comportement normales, y compris l’aptitude à faire une chasse réussie, dans les 48 heures suivant l’immobilisation semble cadrer avec l’hypothèse selon laquelle les ours polaires ne subissent pas d’effets comportementaux de longue haleine après une brève immobilisation chimique à des fins de conservation et de gestion.

The Utility of Harvest Recoveries of Marked Individuals to Assess Polar Bear (Ursus maritimus) Survival

Management of polar bear (Ursus maritimus) populations requires the periodic assessment of life history metrics such as survival rate. This information is frequently obtained during short-term capture and marking efforts (e.g., over the course of three years) that result in hundreds of marked bears remaining in the population after active marking is finished. Using 10 additional years of harvest recovery subsequent to a period of active marking, we provide updated estimates of annual survival for polar bears in the Baffin Bay population of Greenland and Canada. Our analysis suggests a decline in survival of polar bears since the period of active marking that ended in 1997; some of the decline in survival can likely be attributed to a decline in springtime ice concentration over the continental shelf of Baffin Island. The variance around the survival estimates is comparatively high because of the declining number of marks available; therefore, results must be interpreted with caution. The variance of the estimates of survival increased most substantially in the sixth year post-marking. When survival estimates calculated with recovery-only and recapture-recovery data sets from the period of active marking were compared, survival rates were indistinguishable. However, for the period when fewer marks were available, survival estimates were lower using the recovery-only data set, which indicates that part of the decline we detected for 2003 – 09 may be due to using only harvest recovery data. Nevertheless, the decline in the estimates of survival is consistent with population projections derived from harvest numbers and earlier vital rates, as well as with an observed decline in the extent of sea ice habitat.La gestion des populations d’ours polaires (Ursus maritimus) nécessite l’évaluation périodique des mesures du cycle biologique, tel que le taux de survie. Cette information est souvent obtenue dans le cadre des efforts de capture et de marquage à court terme (par exemple, sur une période de trois ans) qui se traduisent par le marquage d’une centaine d’ours au sein de la population une fois les travaux terminés. En nous appuyant sur dix années supplémentaires de données de récoltes de reprises suivant une période de marquage actif, nous aboutissons à des estimations actualisées de la survie annuelle des ours polaires faisant partie de la population de la baie de Baffin du Groenland et du Canada. Notre analyse suggère qu’il y a eu un déclin sur le plan de la survie des ours polaires depuis la période de marquage actif qui a pris fin en 1997. Une partie de ce déclin en matière de survie peut être attribuable à la diminution de la concentration de glace printanière sur le plateau continental de l’île de Baffin. La variance entourant les estimations de survie est comparativement élevée en raison du nombre à la baisse de marquages disponibles. Il y a donc lieu de faire preuve de prudence dans l’interprétation des résultats. La variance des estimations de survie augmentait considérablement au cours de la sixième année suivant le marquage. Lorsque nous avons comparé les estimations de survie avec les ensembles de données de reprise seulement et celles de recapture et de reprise pour la période de marquage actif, les taux de survie étaient indistinguables. Cependant, pour la période pendant laquelle un moins grand nombre de marquages était disponible, les estimations de survie étaient moins élevées lorsque nous nous sommes appuyés sur l’ensemble des données de reprise seulement, ce qui indique qu’une partie du déclin que nous avons constaté pour les années 2003 à 2009 pourrait être attribuable au fait que nous n’avons utilisé que les données des récoltes de reprises. Néanmoins, le déclin en matière d’estimations de survie est conforme aux projections de population dérivées des résultats des récoltes et des indices vitaux antérieurs, ainsi qu’à la diminution qui a été observée sur le plan de l’étendue de l’habitat de la glace de mer

Correlated velocity models as a fundamental unit of animal movement : synthesis and applications

Background: Continuous time movement models resolve many of the problems with scaling, sampling, and interpretation that affect discrete movement models. They can, however, be challenging to estimate, have been presented in inconsistent ways, and are not widely used. Methods: We review the literature on integrated Ornstein-Uhlenbeck velocity models and propose four fundamental correlated velocity movement models (CVM's): random, advective, rotational, and rotational-advective. The models are defined in terms of biologically meaningful speeds and time scales of autocorrelation. We summarize several approaches to estimating the models, and apply these tools for the higher order task of behavioral partitioning via change point analysis. Results: An array of simulation illustrate the precision and accuracy of the estimation tools. An analysis of a swimming track of a bowhead whale (Balaena mysticetus) illustrates their robustness to irregular and sparse sampling and identifies switches between slower and faster, and directed vs. random movements. An analysis of a short flight of a lesser kestrel (Falco naumanni) identifies exact moments when switches occur between loopy, thermal soaring and directed flapping or gliding flights. Conclusions: We provide tools to estimate parameters and perform change point analyses in continuous time movement models as an R package (smoove). These resources, together with the synthesis, should facilitate the wider application and development of correlated velocity models among movement ecologists.Peer reviewe

The Northwest Passage opens for bowhead whales

The loss of Arctic sea ice is predicted to open up the Northwest Passage, shortening shipping routes and facilitating the exchange of marine organisms between the Atlantic and the Pacific oceans. Here, we present the first observations of distribution overlap of bowhead whales (Balaena mysticetus) from the two oceans in the Northwest Passage, demonstrating this route is already connecting whales from two populations that have been assumed to be separated by sea ice. Previous satellite tracking has demonstrated that bowhead whales from West Greenland and Alaska enter the ice-infested channels of the Canadian High Arctic during summer. In August 2010, two bowhead whales from West Greenland and Alaska entered the Northwest Passage from opposite directions and spent approximately 10 days in the same area, documenting overlap between the two populations