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Adaptive radiation and functional morphology
The Salmon Forest Project
Molecular Studies
Lab members

Diurnal and nocturnal foraging behaviour of coastal bears

Dan Klinka
MSc Student
Department of Biology
University of Victoria


Spirit bear
On the west coast of North America, bears are major consumers of salmon and are important agents of salmon nutrient transfer from aquatic to terrestrial habitats. The salmon spawning period is critical to coastal bears as they receive most (33-94%) of their yearly protein from salmon, and this positively effects their body size, population productivity, mean litter size, and population density.

Grizzly cub

Reimchen observed extensive nocturnal foraging by bears in salmon streams on the southern end of Haida Gwaii (Queen Charlotte Islands) and on average, bears were more successful at salmon capture during darkness than during daylight. My research interests focus on the behavioural ecology of mainland coastal black bears and grizzly bears during daylight and darkness and how the foraging behaviour contributes to the nutrient flow dynamics inherent to these salmon systems. At present, I have found that these bears also fish throughout the day and night, and have slightly higher capture success during darkness than in daylight. 


We suggest that darkness is a preferred foraging period as a consequence of increased access to high quality feeding areas, reduced evasive tendencies of the salmon and high capture efficiencies. Bears appear to exploit the salmon spawning period to maximize consumption rates of an ephemeral resource.

Black bear with fish in mouth
Spirit bear at night

Part of this research is also focussed on the ‘spirit bear’ a  white morph of the coastal black bear. The spirit bear occurs at about 10-20% frequency on Princess Royal Island and Gribbell Island near the mid coast of British Columbia. We are investigating the behavioural interactions between the colour morphs during daylight and darkness and examining niche interactions through the analyses of nitrogen and carbon isotopes.

As well as expanding our understanding of the life history and ecological role of the largest carnivores in North America, this research may also provide basic insight into alternate sensory modes used by tetrapods during nocturnal behaviour.

Black and white