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Hunting Behavior of a Marine Mammal Beneath the Antarctic Fast Ice

Hunting Behavior of a Marine Mammal Beneath the Antarctic Fast Ice. R.W. Davis, L.A. Fuiman, T.M. Williams, S.O. Collier, W.P. Hagely, S.B. Kanatous, S. Kohin, M. Horning. (1999). Science, 283: 993-996. Biology 457 Presented by Kimberly Forbes. Background.

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Hunting Behavior of a Marine Mammal Beneath the Antarctic Fast Ice

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  1. Hunting Behavior of a MarineMammal Beneath theAntarctic Fast Ice R.W. Davis, L.A. Fuiman, T.M. Williams, S.O. Collier, W.P. Hagely, S.B. Kanatous, S. Kohin, M. Horning. (1999). Science, 283: 993-996. Biology 457 Presented by Kimberly Forbes

  2. Background • Little known about marine mammal foraging behavior • Difficulty with observation • Previous methods insufficient (a) based on indirect information (b) don’t allow direct observation

  3. Purpose & Method • Purpose To gain insight of the foraging behavior of marine mammals. In particular: (a) how do they find their prey? (b) where do they find their prey? (c) how do they stalk and capture their prey? • Method Observe Weddel Seal foraging behavior through the use of animal-borne video system and data recorder in order to compute their 3-D dive path.

  4. Weddel Seal • Leptonychotes weddellii • Large marine predator • Feeds on small, nototheniid fish and Atlantic cod

  5. Experiment • Attach video system to 4 seals • Occurred between Oct.-Dec., 1997 • Fast ice environment of McMurdo Sound, Antarctica • Recorded time, depth, water speed, bearing, stroke frequency, and ambient sound

  6. Figure 1a & 1b Breathing hole Point of contact • Travel path = 760m • Did not veer horizontally prior to viewing cod • Accelerated and changed horizontal direction upon viewing cod • Non-aggressive contact

  7. Figure 1C • Seal with back-mounted camera • Seal remained out of the cod’s sight • The cod was visible due to backlighting

  8. Figure 2 • Seal followed path of fish to sub-ice area • Seal blew air into crevice to expel fish • Fish expelled, but both escaped • Erect vibrissae Expelled fish

  9. Discussion • Weddell seals don’t use sonar to locate prey. • Not all predator-prey interactions are aggressive. • Seals can come within a close distance (few cm) of the prey without being detected.

  10. Tactics for Foraging • Bite off exposed tail of prey • Flushing out the fish with air • Pursue fish through the platelet ice

  11. Conclusion Vision is important for foraging and interaction with prey. In particular, backlighting is critical for the seal to visualize the prey underneath the fast ice surface.

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