RESEARCH NOTE

The remains of a small cetacean partially consumed by a polar bear observed on sea ice in the Labrador Sea, Canada

Garth d’Entremont¹ & Jon Aars²

¹Pubnico, NS, Canada; ²Research Department, Norwegian Polar Institute, Fram Centre, Tromsø, Norway

Abstract

On 11 April 2026, a polar bear (Ursus maritimus) was observed approximately 150 m from the partially consumed carcass of a small cetacean that lay on the sea ice. The observation was made from a trawler operating in heavy sea ice in the Labrador Sea, about 110 km off the coast of Newfoundland and Labrador, Canada.

Keywords: Dolphins; whales; odontocete; flexible foraging; citizen science

 

 

The observation

On 11 April 2026, about 110 km east–north-east (58°11.54 N, 59°54.57 W) of Cape Mugford, in Newfoundland and Labrador, Canada, a 70-m Arctic class factory freezer trawler was operating in sea ice (Fig. 1). The trawling gear was being hauled in as the tide carried the ship into a ridge of thick, rafted first-year sea ice with about 90% coverage. At 12:45 UTC, as preparations were being made to sail out of the ice, a polar bear (Ursus maritimus; Fig. 2), possibly a young adult male, walked in front of the ship, then turned and walked away from the ship on the starboard side. The bear appeared to be in good condition. The carcass of a small cetacean was then observed on the port side of the vessel (Fig. 3). The bear and the cetacean were approximately 150 m apart before the bear moved off. Based on pictures of the small whale, an odontocete, compared to tracks from the bear and gulls in the snow, it may have been about 2–3 m in length.

Fig. 1 The approximate location (red dot) of the observation in the Labrador Sea.

 

Fig. 2 The polar bear observed on the sea ice off Newfoundland and Labrador. (Photos: Garth d’Entremont.)

 

Fig. 3 The cetacean carcass observed about 150 m away from the polar bear. (Photo: Garth d’Entremont.)

Much of the skin and fat of the carcass had been removed. The remaining skin was a very dark colour. It was not possible to identify the species or to determine with certainty whether it was an adult or a juvenile.

Discussion

Polar bears hunt mainly seals, but they show flexibility in their foraging strategy and have been documented hunting and scavenging whales (e.g., Heide-Jørgensen et al. 2002; Derocher 2012; Gormezano & Rockwell 2013; Gormezano et al. 2017; Laidre et al. 2018; Galicia et al. 2021). The northern part of the Labrador Sea is within the distribution range of several species of small cetaceans, including harbour porpoise (Phocoena phocoena), white-beaked dolphin (Lagenorhynchus albirostris), long-finned pilot whale (Globicephala melas) and northern bottlenose whale (Hyperoodon ampullatus).

Two cetacean species that are more commonly associated with Arctic waters, the narwhal (Monodon monoceros) and the white whale (Delphinapterus leucas), also known as the beluga, also occur in the area. Both species are known to be preyed upon by polar bears (Heide-Jørgensen et al. 2002; Derocher 2012; Gormezano et al. 2017), but they can likely be ruled out in the present case because of the very dark skin colouration of the observed carcass.

Although interactions between polar bears and smaller cetaceans, other than white whales and narwhals, are rarely documented, an exception was reported from Svalbard in April 2014 (Aars et al. 2015). An adult male polar bear was observed with a partly consumed white-beaked dolphin that had become entrapped in sea ice and was presumed to have been killed and hauled up onto the ice. A second dolphin eaten by the same male was found only a few metres away. During the following summer, other bears were seen feeding on the remains of several additional dolphin carcasses in the same area (Aars et al. 2015).

Given the estimated size of the carcass, the dark colouration of the fluke and the location, the carcass reported here was most likely a white-beaked dolphin, although another dolphin species cannot be ruled out.

Polar bears are known to capture small odontocetes that have become trapped in sea ice and forced to breathe in a restricted opening (e.g., Derocher 2012; Heide-Jørgensen et al. 2002). Alternatively, the dolphin may have died when ice cut off its access to air and it was later pulled up onto the ice by the polar bear (possibly more than one polar bear). The scanty blood around the carcass suggests the dolphin may have been dead when the polar bear(s) found it or it had not been killed at the spot where it was photographed. There was a sizeable area of open water in the vicinity of the site where the dolphin was photographed (Fig. 1b), but it is not known when that opened up. Observations such as this are valuable given the few documented records of polar bears feeding on dolphins.

References

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Gormezano L.J., Ellis-Fellege S.N., Iles D.T., Barnas A. & Rockwell R.F. 2017. Polar bear foraging behavior during the ice-free period in western Hudson Bay: observations, origins, and potential significance. American Museum Novitates 2017, article no. 3885, doi: 10.1206/3885.1.

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