Dive shapes reveal temporal changes in the foraging behaviour of different age and sex classes of harbour seals (Phoca vitulina) J. Baechler, C.A. Beck, and W.D. Bowen Abstract: Classifying dives into two-dimensional shapes based on time and depth is an attempt to extract additional in-formation abo...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.540.5740 http://bowenlab.biology.dal.ca/data/BaechlerPvDiveShapesCJZ2002.pdf |
| Summary: | Dive shapes reveal temporal changes in the foraging behaviour of different age and sex classes of harbour seals (Phoca vitulina) J. Baechler, C.A. Beck, and W.D. Bowen Abstract: Classifying dives into two-dimensional shapes based on time and depth is an attempt to extract additional in-formation about the behaviour of aquatic air-breathing predators. In some species, there is considerable circumstantial evidence that different dive shapes represent different behaviours. However, few studies have provided direct evidence of the relationship between dive shape and function. We classified over 283 000 dives of adults (31 males and 45 fe-males) and suckling (13) and recently weaned (15) harbour seal (Phoca vitulina) pups into seven shapes using super-vised discriminant function analysis. Changes in the percentage of U-shaped dives over time within adults and weaned pups were associated with changes in food intake derived from water-flux studies on subsets of the same individuals. The changes in the percentage of U-shaped dives were accompanied by roughly reciprocal changes in V-shaped dives, whereas there was little change in other dive shapes, indicating that V-shaped dives are not generally exhibited during foraging. Video of adult males (from an animal-borne video system) also showed that there was a strong but not exclu-sive association between foraging and U-shaped dives. Our results indicate that changes in the percentage of U-shaped |
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