Magnetic alignment enhances homing efficiency of hunting dogs
- Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Czech Republic
- Biology Department, Barry University, United States
- Department of Ethology, Institute of Animal Science, Czech Republic
- Department of Ethology and Companion Animal Science, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences, Czech Republic
- Department of Zoology and Fisheries, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences, Czech Republic
- Department of Biological Sciences, Virginia Tech, United States
Figures
Figure 1
Still shots of a fox terrier (left column) and a miniature dachshund (right column) used in this study showing the tracking equipment and habitat.
Above: The GPS transmitter and antenna are fixed to a collar and fitted around the animal’s neck (note that for safety and comfort of the animal, the collar is free to rotate). The black fabric …
Figure 2
Spatial features and return strategies derived from GPS data used in analyses.
(A) Schematic illustration of total excursion track. Excursion start marks location of owner when the dog is more than 100 m away, indicating that the dog is pursuing a game animal. Excursion start …
Figure 3
Average speed increases in scouting compared to tracking.
Predicted values of inbound speed (km/hour, LSMEANs ± SE) according to return strategy and independent of the direction of the compass run (azimuth C).
Figure 4
Inbound speed and track length positively correlate with shoulder height and beeline excursion distance, respectively.
Upper row: A bubble-plot of predicted values of inbound speed (km per hour, LSMEANs ± SE) plotted relative to shoulder height (cm). The center of each bubble represents the predictive value and …
Figure 5
Inbound speed (length) and inbound track length (right) influenced by forest paths during the homing return.
Left: Predicted values of inbound speed (km per hour, LSMEANs ± SE) grouped according to whether a portion of the inbound trajectory followed a forest path (‘Followed path’), or if the return was …
Figure 6
Circular distributions for azimuth A and azimuth B means grouped by return strategy.
Circular distributions of magnetic orientation of the direction of the turning point relative to the excursion start/owner (azimuth B) and the initial outbound segment (azimuth A) for scouting (left …
Figure 7
Alignment responses during the initial inbound return (= ‘compass run’) in free-roaming dogs.
(A–D) Circular distributions showing geomagnetic alignment responses during the initial inbound segment (azimuth C, ‘compass run’), when distributions are partitioned into Scouting (A, B) and …
Figure 8
Orientation of the compass run plotted relative to the position of owner.
To test for an influence of the owner on the orientation of the compass run (azimuth C) during scouting, the data was partitioned into four distributions corresponding to when the owner was located …
Figure 9
Compass run improves homing performance during scouting.
Comparison of predicted values of the probability of log-transformed homing efficiency index (LSMEANs ± SE) between dogs exhibiting a compass run oriented along the ~north south (±45°) compared to …
Videos
Video 1
Example of all three phases of an excursion.
Labels of the left side of the video indicate the segment of the excursion. The video begins with the excursion start (i.e. the beginning of the outbound trajectory) when the dog becomes separated …
Video 2
Example video showing the compass run behaviour during a scouting strategy return.
The GPS track is shown on the right half of the video with the red ‘bulls-eye’ tracker synced with the video shown on the left. The bulls-eye tracker moves across the track corresponding to the …
Additional files
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Source data 1
Basic raw data used in calculations.
- https://cdn.elifesciences.org/articles/55080/elife-55080-data1-v1.xlsx
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Supplementary file 1
Information on subjects studied, parameters included in the analyses, and results of circular statistics.
(A) Table 1 Information about dogs used in the study. Owner = initials of owner accompanying dog during walks, Age = age or age-range during the study period, NOUT = number of outbound trajectories, NIN = total number of inbound trajectories, NT = number of inbound returns using a tracking strategy, NS = number of returns using a scouting strategy. (B) Table 2 Factors in the final GLMMs for the dependent variables (in bold). a) probability for N-S alignment (±45°) during the initial inbound segment (i.e. ‘compass run’); b) probability for scouting strategy; c) efficiency of return; d) speed of inbound trajectory; e) inbound track length. (C) Table 3 Effects used in General Linear Mixed Models. (D) Table 4 Length parameters during different phases of the excursion (data from combined strategies are excluded). (E) Table 5 Circular analyses of individual (‘raw’) and grouped means for azimuth A, B and C during scouting and tracking strategies, and when a scouting strategy was used as the second return strategy (tracking used as a second return strategy not shown). Means were calculated by averaging directional headings for each dog, then calculating a grand mean from all individuals. Raw data were calculated by treating each azimuth as an independent bearing. Note that due to the bimodal preference found within individual dogs for azimuth C, these bearings were treated as axial data. See Figures 6–8. (F) Table 6 Axial analyses of azimuth C (=orientation of the compass run) partitioned into four groups to test for an influence of the owner on the orientation of the compass run during scouting strategy returns. Each analysis corresponds to the orientation of the compass run when the owner was located in one of four cardinal compass directions (±45°) relative to the turning point. Therefore, owner positions relative to the turning point are: owner = magnetic ~ north (316°−45°),~east (46°−135°),~south (136°−225°), or ~west (226°−315°). All data are treated as independent bearings. (See Figure 8).
- https://cdn.elifesciences.org/articles/55080/elife-55080-supp1-v1.docx
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Transparent reporting form
- https://cdn.elifesciences.org/articles/55080/elife-55080-transrepform-v1.pdf
