Publication Date:
2017-04-04
Description:
Background: Laboratory and field experiments have provided evidence that sea turtles use geomagnetic cues to navigate
in the open sea. For instance, green turtles (Chelonia mydas) displaced 100 km away from their nesting site were impaired in
returning home when carrying a strong magnet glued on the head. However, the actual role of geomagnetic cues remains
unclear, since magnetically treated green turtles can perform large scale (.2000 km) post-nesting migrations no differently
from controls.
Methodology/Principal Findings: In the present homing experiment, 24 green turtles were displaced 200 km away from
their nesting site on an oceanic island, and tracked, for the first time in this type of experiment, with Global Positioning
System (GPS), which is able to provide much more frequent and accurate locations than previously used tracking methods.
Eight turtles were magnetically treated for 24–48 h on the nesting beach prior to displacement, and another eight turtles
had a magnet glued on the head at the release site. The last eight turtles were used as controls. Detailed analyses of water
masses-related (i.e., current-corrected) homing paths showed that magnetically treated turtles were able to navigate toward
their nesting site as efficiently as controls, but those carrying magnets were significantly impaired once they arrived within
50 km of home.
Conclusions/Significance: While green turtles do not seem to need geomagnetic cues to navigate far from the goal, these
cues become necessary when turtles get closer to home. As the very last part of the homing trip (within a few kilometers of
home) likely depends on non-magnetic cues, our results suggest that magnetic cues play a key role in sea turtle navigation
at an intermediate scale by bridging the gap between large and small scale navigational processes, which both appear to
depend on non-magnetic cues.
Description:
Published
Description:
e26672
Description:
1.6. Osservazioni di geomagnetismo
Description:
3.8. Geofisica per l'ambiente
Description:
JCR Journal
Description:
open
Keywords:
geomagnetic field
;
magnetic anomalies
;
pigeons magnetic homing
;
03. Hydrosphere::03.04. Chemical and biological::03.04.99. General or miscellaneous
;
04. Solid Earth::04.05. Geomagnetism::04.05.04. Magnetic anomalies
;
04. Solid Earth::04.05. Geomagnetism::04.05.09. Environmental magnetism
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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