Examination of head versus body heading may help clarify the extent to which animal movement pathways are structured by environmental cues?
Creators: name: Gunner, Richard
Publisher: name: Zenodo
Year: 2023
Subjects: Animal Behaviour
decision-making
animal heading

description: Understanding the processes that determine how animals allocate time to space is a major challenge, althoughit is acknowledged that summed animal movement pathways over time must define space-time use. The criticalquestion is then, what processes structure these pathways? Following the idea that turns within pathways mightbe based on environmentally determined decisions, we equipped Arabian oryx with head- and body-mounted tagsto determine how they orientated their heads – which we posit is indicative of them assessing the environment– in relation to their movement paths, to investigate the role of environment scanning in path tortuosity. Aftersimulating predators to verify that oryx look directly at objects of interest, we recorded that, during routinemovement, > 60% of all turns in the animals' paths, before being executed, were preceded by a change in headheading that was not immediately mirrored by the body heading: The path turn angle (as indicated by the bodyheading) correlated with a prior change in head heading (with head heading being mirrored by subsequent turnsin the path) twenty-one times more than when path turns occurred due to the animals adopting a body headingthat went in the opposite direction to the change in head heading. Although we could not determine what theobjects of interest were, and therefore the proposed reasons for turning, we suggest that this reflects the use ofcephalic senses to detect advantageous environmental features (e.g. food) or to detect detrimental features (e.g.predators). The results of our pilot study suggest how turns might emerge in animal pathways and we proposethat examination of points of inflection in highly resolved animal paths could represent decisions in landscapesand their examination could enhance our understanding of how animal pathways are structured.
description: All data analysis was performed in R.
Funding provided by: Researchers supporting project number RSPD2023R602 from King Saud University*Crossref Funder Registry ID: Award Number: 
Funding provided by: Deanship of Scientific Researchat the King Saud University through Vice Deanship of Research Chairs*Crossref Funder Registry ID: Award Number: 
Funding provided by: National Geographic Global Exploration Fund *Crossref Funder Registry ID: Award Number: 
Funding provided by: Royal Society/Wolfson Lab refurbishment scheme*Crossref Funder Registry ID: Award Number:
description: Six Arabian oryx, from a herd of 12 semi-captive animals kept within a 0.5 X 0.5 km natural enclosure within the Imam Saud bin Abdulaziz Royal Nature Reserve (previously called Mahazat as-Sayd), a protected area located in west-central Saudi Arabia (41.58, 22.34), were equipped with head- and body-mounted tags (Daily Diary – standard model; http://www.wildbytetechnologies.com/tags.html) that recorded tri-axial acceleration at 40 Hz and tri-axial magnetic field intensity at 13 Hz using a real-time clock base. The head-mounted tags were glued between the horns while the body-mounted units were attached to a collar and weighted to hang ventrally. The collar also had a dorsally mounted GPS, set to determine location once every 15 mins. Although the real time clocks in the devices were reported to have maximum drift of no more than a few seconds per month, all units were calibrated to synchronize time properly. Tag heading were derived from both head- and collar-mounted tags, using the tilt-compendated compass method.

The animals were then allowed to roam freely within their enclosure for 7 days. On day 3, we selected a single period of ca. 5 h of behaviour for each individual, during which the focal animals were predominantly moving, as indicated by Vectorial sum of the Dynamic Body Acceleration having values >0.1 g.

After recovery of the tags, the individual head- and body-headings from all animals for all periods were determined (using methods described in https://doi.org/10.1186/s40317-021-00245-z) as well as times when 'significant turns' in either metric occurred (using methods outlined in https://doi.org/10.1111/2041-210X.13056). This datset contains the animal heading (0-360°) and Vectorial sum of the Dynamic Body Acceleration (g) for both sets of tags per individual for the ca. 5 h of predominantly moving behaviour. The provided R code serves as an example for processing head and body headings, aimed at identifying 'significant turns' and quantifying the magnitude of heading change for each turn.