Proximity loggers on amphibious mammals: a new method to study social relations in their terrestrial habitat
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Research Areas
Publication Details
Output type: Journal article
Author list: Meise K, Kruger O, Piedrahita P, Mueller A, Trillmich F
Publisher: Inter Research
Publication year: 2013
Volume number: 18
Issue number: 1
Start page: 81
End page: 89
Number of pages: 9
ISSN: 1864-7782
eISSN: 1864-7790
Languages: English-Great Britain (EN-GB)
Unpaywall Data
Open access status: gold
Full text URL: https://www.int-res.com/articles/ab2013/18/b018p081.pdf
Abstract
Amphibious mammal species alternate between foraging at sea and attendance on land. Due to thermoregulatory requirements, they often haul out during the night, making social interactions difficult to observe. We tested the suitability of UHF-proximity loggers for assessing social relationships among Galapagos sea lions Zalophus wollebaeki. To survive periods at sea, proximity loggers were embedded in epoxy. Automatic downloads to receiving stations rendered logger recovery unnecessary. Encounters were logged within a range of 10 m. Logs provided information about interacting individuals as well as time and duration of encounters. 'Received signal strength indicator' values correlated with distance, but were influenced by antenna angle and environmental factors. Laboratory tests and validation in the field demonstrated that the spatial resolution corresponded to 2 m. Data needed to be corrected, as single encounters were recorded as multiple logs and reciprocity of loggings between animals was not always achieved. Digital data correlated with observational data, but associations were 4 times more likely to be detected using proximity loggers. Data revealed that non-territorial males frequently associated for extended periods of time, especially during the night and even outside the study colony. The modified proximity logger system proves an excellent tool to determine social structure in situations where direct observation is limited.
Keywords
Amphibious species, Proximity logger, Social structure
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