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Harbor seals (Phoca vitulina) can perceive optic flow under water
Nele Gläser1, Björn Mauck2, Farid I Kandil3
1University of Rostock, Institute for Biosciences, Sensory and Cognitive Ecology, Rostock, Germany.
Plos One
|July 25, 2014
Summary
Harbor seals can perceive underwater optic flow, using this visual information to determine their heading. This finding suggests optic flow is a crucial sensory tool for aquatic locomotion and orientation in many species.
Area of Science:
- Sensory Ecology
- Animal Behavior
- Vision Science
Background:
- Optic flow, the visual perception of motion during self-movement, is well-studied in aerial animals but less so in aquatic environments.
- Despite potential visual impairments in turbid waters, optic flow could provide vital self-motion information to aquatic organisms.
Purpose of the Study:
- To investigate underwater optic flow perception in a semi-aquatic mammal, the harbor seal.
- To determine if seals can use optic flow to discern their heading and orientation underwater.
Main Methods:
- Simulated forward movement using an underwater projection displaying a dot cloud, creating optic flow patterns.
- A behavioral task where seals judged deviations of a superimposed cross from the focus of expansion (simulated heading).
Main Results:
- Harbor seals successfully perceived the simulated underwater optic flow.
- Seals could determine deviations from the simulated heading with a visual angle threshold of 0.6 degrees.
Conclusions:
- Optic flow is a viable sensory modality for harbor seals and likely other aquatic species for locomotion and orientation.
- Optic flow perception appears to be a universally utilized visual tool among mobile organisms with eyes.
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