Arctic polar bear found eating, caching dolphins
Researchers, for the first time ever, have documented a bear preying on two white-beaked dolphins on a small fjord in Svalbard, Norwegian High Arctic.
Though polar bears have been known to prey on a variety of species, it is for the first time that a bear has been seen preying on dolphins. The observations were made by researchers in April last year and according to researchers, the dolphins may have been trapped in the ice after strong northerly winds the days before, and possibly killed when forced to surface for air at a small opening in the ice.
The researchers, in their paper entitled “White-beaked dolphins trapped in the ice and eaten by polar bears”, note that the bear had consumed most parts of one dolphin. Further, he was in the process of covering the mostly intact second dolphin with snow – which researchers call caching. They say that caching behaviour is generally considered untypical of polar bears.
In their extended observations, during the ice-free summer and autumn, researchers observed at least seven different white-beaked dolphin carcasses in or near the same area. They suggest that the dolphins were likely from the same pod and also suffered death due to entrapment in the ice in April.
Researchers add in their report that no recording of the species has been made in winter or spring this far north in Svalbard. The fjords and around the coast of northern Spitsbergen, an area normally covered by annual ice, were ice-free in winter 2013/14. It is likely that the presence of the dolphins in early spring was due to the lack of sea ice in the period prior to their observation.
Researchers conclude that their observations indicate entrapments of pods of white-beaked dolphins may provide a significant source of food for some bears locally over a longer period of time after such an incident.
Effect of Arctic sea meltdown on marine mammals
In a study published earlier this year in March, researchers for the first-ever time have gauged the ecological status of marine mammals living in the Arctic and the effect which the meltdown of ice and temperature increase in the region is having on these mammals.
Researchers claim that for the Arctic marine mammals, the future is especially uncertain owing to loss of sea ice and warming temperatures. The University of Washington study, assessing the status of all circumpolar species and subpopulations of Arctic marine mammals, including seals, whales and polar bears, underscores the precarious state of those mammals and outlines the current state of knowledge and their recommendations for the conservation of these animals over the 21st century.
Lead author Kristin Laidre said that these species are not only icons of climate change, but they are indicators of ecosystem health, and key resources for humans.
The overall numbers and trends due to climate change are unknown for most of the 78 populations of marine mammals included in the report: beluga, narwhal and bowhead whales; ringed, bearded, spotted, ribbon, harp and hooded seals; walruses; and polar bears.
Accurate scientific data, currently lacking for many species, will be key to making informed and efficient decisions about the conservation challenges and tradeoffs in the 21st century, said Laidre.
Despite the lack of data, researchers have said that the species most at risk from the changes are polar bears and ice-associated seals. Laidre said that these animals require sea ice to find food, find mates and reproduce, to rear their young. It’s their platform of life. It is very clear those species are going to feel the effects the hardest.
Whales may actually benefit from less ice cover, at least initially, as the open water could expand their feeding habitats and increase food supplies. Approximately 78 per cent of the Arctic marine mammal populations, included in the study, are legally harvested for subsistence across the Arctic.
There’s no other system in the world where top predators support human communities the ways these species do, Laidre said.