2016-2017 USAP Field Season
Geomagnetic navigation by Weddell seals beneath Antarctic ice
Dr. Randall Davis
Texas A & M University
Supporting Stations: McMurdo Station
Do Weddell seals possess a magnetic sense and use it to sense Earth's geomagnetic field for navigating under sea ice over small spatial scales? The primary objectives of this project are to determine: (1) Whether Weddell seals diving under shore-fast sea ice respond predictably to spatial variations in Earth's magnetic field; (2) How the seals use information obtained from earth's magnetic field to return to the vicinity of known breathing holes; (3) Whether light intensity and day length affect seal responses to differences in earth’s magnetic field; and (4) Whether energetic efficiency of navigation by Weddell seals is altered by differences in earth’s magnetic fields. To achieve those objectives, researchers will conduct experiments on translocated Weddell seals in which they will measure changes in behavioral and energetic responses of individuals to different geomagnetic field properties and test those responses against precise predictions. By conducting experiments during periods of high light intensity and long day length (October and November) and low light intensity and reduced day length (mid August and September), and by documenting the orientation of fixed sound sources and water currents, the experiment should identify a geomagnetic response and eliminate other sensory modalities.
Field Season Overview
Researchers will make day trips by Pisten Bully to two sea ice camps on McMurdo Sound during Winfly and three locations during Mainbody. The team will capture Wedell seals, perform controlled releases, take metabolic measurements and recover instrumentation temporarily mounted on the seals. Each location will have a fish hut placed over a 1.2 meter diameter hole in the sea ice. Instrumented seals will be consecutively released into each of the three holes in order to observe their behavior as they experience different geomagnetic fields.
Deploying Team Members