Data from: Sex, body size, and boldness shape the seasonal foraging habitat selection in southern elephant seals
Data files
Nov 17, 2025 version files 127.38 MB
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boldness_test_data.txt
21.50 KB
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dive_data.txt
44.98 MB
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habitat_selection_data.txt
1.30 MB
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location_data.txt
26.04 MB
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metadata.txt
7.37 KB
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README.md
4.32 KB
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salinity_temperature_data.txt
55.02 MB
Abstract
Selecting foraging habitat is a fundamental behaviour in the life of organisms as it directly links resource acquisition to fitness. Differences in habitat selection among individuals may arise from several intrinsic and extrinsic factors, and yet, their interaction has been given little attention in the study of wild populations.
We combine sex, body size, and boldness to explain individual differences in the seasonal foraging habitat selection of southern elephant seals (Mirounga leonina) from the Kerguelen Archipelago. We hypothesize that habitat selection is linked to the trade-off between resource acquisition and risk, and that individuals differ in their position along this trade-off because of differences in reproductive strategies, life stages, and metabolic requirements.
Before the post-moult foraging trip, we used a novel object approach test to quantify the boldness of 28 subadult and adult females and 42 subadult males and equipped them with data loggers to track their movements at sea.
Subadult males selected neritic and oceanic habitats, whereas females mostly selected less productive oceanic habitats. Both sexes showed a seasonal shift from Antarctic habitats in the south in the summer to the free of ice subantarctic and subtropical habitats in the north in the winter. Males avoided oceanic habitats and selected more productive neritic and Antarctic habitats with body size mostly in the winter. Bolder males selected northern warmer waters in winter, while shyer ones selected the Kerguelen plateau and southern colder oceanic waters. Bolder females selected the Kerguelen plateau in the summer when prey profitability is assumed to be the highest.
This study provides new insights on the spatiotemporal foraging ecology of elephant seals in relation to personality, but also emphasizes the relevance of combining several intrinsic and extrinsic factors in understanding among-individual variation in space use essential in wildlife management and conservation.
https://doi.org/10.5061/dryad.g1jwstqs6
Description of the data and file structure
Files and variables
File: boldness_test_data.txt
Description:
Variables
- animal_id : seal id
- datetime : date and time (utc) of the test
- observation_id : novel object approach test id
- tester_id : tester id
- head : the percentage of time the seal head was up in a low position
- head_high : the percentage of time the seal head was up in a high position
- stand : the percentage of time the seal was standing in a low position
- stand_high : the percentage of time the seal was standing in a high position
- mouth : the percentage of time the seal mouth was opened
- vocalization : the percentage of time the seal was vocalizing
- attack : the percentage of time the seal was moving its head or the whole body towards the camera
- retreat : the percentage of time the seal was moving away from the camera
- boldness : boldness score as the first principal component from a principal component analysis of all behavioural traits measured from the test
- replicate : number of the replicate
- approach : approach direction of the tester (Front or Side)
- position : position of the focal seal (Straight, Not straight)
- nb_ind_3m : number of seals within a 3 m radius around the focal seal
- position_in_huddling: position in huddling (No, Edge, Inside)
- nb_capture : the number of times the focal seal was captured
File: habitat_selection_data.txt
Description:
Variables
- animal_id: seal id
- trip_id : trip id
- season : season (summer or winter)
- habitat : habitat category
- foraging : foraging state (1) or not (0)
- sex : seal sex
- boldness : boldness score
- length_cm: length in centimeters
File: metadata.txt
Description:
Variables
- animal_id : seal id
- animal_name : seal name
- flippertag_id : seal flipper tag id
- datetime : ctd logger attachment date and time in utc
- site : site of logger deployment
- year : year of logger deployment
- sex : seal sex
- ctd_body_num : argos number of the ctd logger
- ctd_reference_num: reference number of the ctd logger
- mass_kg : mass of the seal in kilograms
- length_cm : length of the seal in centimeters
File: dive_data.txt
Description:
Variables
- animal_id : seal id
- dive_id : dive id
- trip_id : trip id
- datetime : date and time in utc of the dive
- ctd_reference_num: reference number of the ctd logger
- surf_dur : post-dive surface duration in seconds
- dive_dur : dive duration in seconds
- max_dep : dive maximum depth in meters
- d1,d2,d3,d4 : intermediate depth points (meters) in the dive
- t1,t2,t3,t4 : the percentage of the dive duration elapsed since the beginning of the dive at each of the intermediate depth points
File: location_data.txt
Description:
Variables
- animal_id : seal id
- trip_id : trip id
- ctd_reference_num : reference number of the ctd logger
- datetime : location date and time in utc
- lq : argos location class
- lat : latitude in decimal degrees
- lon : longitude in decimal degrees
- semi_major_axis : length of the error ellipse semi-major axis in meters
- semi_minor_axis : length of the error ellipse semi-manor axis in meters
- ellipse_orientation: error ellipse orientation in degrees (from North when heading East)
- error_radius : error radius in meters
- tag_type : tag type (ctd)
File: salinity_temperature_data.txt
Description:
Variables
- animal_id : seal id
- trip_id : trip id
- profile_id : salinity/temperature profile id
- datetime : date and time in utc
- depth : depth in meters
- temperature: temperature in Celsius degrees
- salinity : salinity in psu
