Plains zebra time budgets, social behavior, and communication during the 2021-2022 Laikipia-Samburu ecosystem drought

Hex, Severine1 ; Isbilen, Erin2 ; Rubenstein, Daniel1

Published May 08, 2024 on Dryad. https://doi.org/10.5061/dryad.x0k6djht3

Data files

May 08, 2024 version files 20.92 MB

Dataset_S1.xlsx

10.27 MB
Dataset_S2.xlsx

9.87 MB
Dataset_S3.xlsx

277.39 KB
Dataset_S4.xlsx

168 KB
Dataset_S5.xlsx

72.44 KB
Dataset_S6.xlsx

15.46 KB
Dataset_S7.xlsx

203.89 KB
Dataset_S8.xlsx

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README.md

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Abstract

Anthropogenically induced climate change has significantly increased the frequency of acute weather events, such as drought. As human activities amplify environmental stresses, animals may be forced to prioritize survival over behaviors less crucial to immediate fitness, such as socializing. Yet, social bonds may also buffer organisms from the deleterious effects of environmental conditions. We investigated how the highly social plains zebra (Equus quagga) modify their activity budgets, social networks, and multimodal communication during a drought. This dataset contains a) activity budget, b) steps per minute as a proxy for foraging effort, c) nearest neighbor association data, d) interaction rate, e) juvenile social interaction partner data, and f) multimodal communication data.

README: Plains zebra time budgets, social behavior, and communication during the 2021-2022 Laikipia-Samburu ecosystem drought

This dataset comprises the activity budgets, social association data, social interactions, and multimodal communication of wild plains zebras(Equus quagga) collected in the summers of 2021 and 2022, during which time a severe drought was experienced in the Laikipia-Samburu ecosystem. Data were collected from videos collected during focal follows of 21 known focal harems, from which we extracted social and self-maintenance behaviors, steps-per-minute, rate of social interaction, nearest-neighbor association data, and social interactions.

Multimodal communication was coded from videos to define the full suite of visual, acoustic, tactile, and chemical signals being produced. Data were subsequently used to construct co-occurrence networks of multimodal communication.

Description of data and file structure

All datasets have a "Key" tab with definitions of the columns and their
units.

Dataset S1. Complete dataset used to construct plains zebra time budgets for 2021 and 2022.

For a subset of data, Begin time and End time have an "na" value. These were manually recorded travel bouts. As it is challenging to extract meaningful behavior from video recordings taken while the vehicle is in motion, if individuals engaged in continuous travel for an extended duration (>15 continuous minutes), we terminated the video recording and manually recorded the duration of travel for later integration into time budget calculations.

Dataset S2. Complete dataset used to calculate steps/minute for 2021 and 2022.

Dataset S3. Complete dataset of focal follow nearest neighbor scan samples for 2021 and 2022. Empty cells in Nearest2 column are equivalent to an N/A, meaning there was no second individual within one body length of the focal individual.

Dataset S4. Complete dataset of full harem nearest neighbor scan samples for 2021 and 2022. Empty cells in the Nearest column are equivalent to an N/A, meaning there was no individual within one body length of the focal individual.

Dataset S5. Complete dataset of interactions/30 minutes for 2021 and 2022.

Dataset S6. Complete dataset of juvenile social interaction partners 2021 and 2022.

Dataset S7. Complete dataset used to construct plains zebra multimodal communication networks for 2021 and 2022.

Dataset S8. Body condition scores of individuals in 2021 and 2022.

Each row represents an observed configuration of visual, tactile, acoustic, and/or chemical signals seen in a given moment in time. "Begin_Time" and "End_Time designate the time in the video that the given configuration was observed, while "Duration" designates how long the given posture was observed. All three are in "hh:mm:ss" format.

The entire body, "Ears", "Eyes", "Upper_Lip", "Corner_of_Lip", "Jaw", "Head_Neck_Position", and "Tail" are represented for each posture except for instances where there were mutually exclusive or redundant states
(e.g. "jaw open" and "bite"). All other potential components were coded only as observed, and therefore may not be present in every observation.

R Code S1. R code used to conduct all analyses and construct all visualizations.

Methods

Ethical statement

This study was conducted on a population of wild plains zebras living in Ol Pejeta Nature Conservancy (0°00 N, 36°56 E), in Laikipia, Kenya. All research was conducted with the permission of Ol Pejeta Nature Conservancy and the Kenyan Ministry of Wildlife (NACOSTI/P/21/11647) and was in compliance with the guidelines of the Princeton University Institutional Animal Care and Use Committee (1835F).

Study animals

Our sample comprised 21 focal harems with an average harem size of 5 members (2-13 individuals) (Table S1). This population has been monitored continuously since 2008, and we have pedigrees of all focal individuals. We were able to individually identify zebras based on their unique stripes. Individuals were classified into one of four age/sex classes: stallion, non-lactating female, lactating female, and juvenile (Table S2). Juveniles were defined as pre-dispersal individuals, including pre-dispersed, sexually mature males as old as 4 years (N = 4 in 2021, N = 2 in 2022), who are nonreproductive and still operate in the juvenile social niche (Klingel, 1965; personal observation).

Data collection

Data collection occurred daily between July 13th and September 30th, 2021 (hereafter “early drought”), and June 13th and August 12th, 2022 (hereafter “late drought”). Two focal follows were conducted each day by vehicle, the first occurring between 08:00-12:00 and the second between 12:30-16:30. A single harem was the subject of each observation period, and two harems were followed per day. At the beginning of each observation period, we recorded the presence or absence of members, including newly born foals, and scored the body condition of each individual using the plains zebra body condition scale, a qualitative measure of overall body condition (Ginsberg, 1988). Within each observation period, a single individual from the harem was selected as the focal animal, to be followed for two consecutive 30 minute blocks before a new focal individual was selected. The focal individual’s behavior was continuously captured using a Canon Vixia HR R700, and a Sennheiser ME66 directional microphone in a Rode Blimp windshield and a Tascam Dr-100MKII Linear PCM recorder sampling at 48kHz. As it is challenging to extract meaningful behavior from video recordings taken while the vehicle is in motion, if individuals engaged in continuous travel for an extended duration (>15 continuous minutes), we terminated the video recording and manually recorded the start and end time of travel for later integration into time budget calculations. Between each 30-minute block, we conducted a scan sample of the entire harem and recorded the behavior and nearest neighbor of each member of the harem, operationalized as being within one body length.

All video was coded for behaviors of interest using ELAN video annotation software (version 4.8.1). To investigate changes in activity budget across years, we coded 1 to 3 equally spaced five-minute sub-samples from each video (i.e. 5-10 minutes, 15-20 minutes, 25-30 minutes), depending on the video length. We scored nearest neighbor of the focal animal every five minutes. Within the sub-samples, we counted steps-per-minute. We also scored all activities performed by the focal animal during the sub-samples to construct time budgets (Table 2). Social behaviors were grouped into two broad categories, “passive socializing”, which were defined as proximity-based social behaviors produced concurrently with a self-maintenance behavior (i.e. resting in physical contact, grazing side-by-side), and “active socializing”, which included dedicated social behaviors with no additional self-maintenance function (e.g. aggression, affiliation, etc.).

To analyze multimodal communication, we coded all interactions captured by our focal follow videos. Our coding scheme is published in detail elsewhere (Hex & Rubenstein, 2024). In brief, we coded all concurrent visual, acoustic, tactile, and/or chemical signals produced. An interaction was defined as beginning when two individuals entered one body length of one another and the sender was 1) oriented towards the receiver, 2) the signal was produced in the direction of the receiver, 3) the sender approached the receiver, and/or 4) the sender made physical contact with the receiver. An interaction was defined as terminated when either 1) one individual moved beyond one body length of the other without being followed, or 2) the parties ceased interacting for at least 10 seconds (e.g., began to graze or sleep in proximity).

We only coded interactions in which the video was zoomed in enough for reliable coding of all areas of interest, and in which the focal individual was in focus and entirely in frame, unobscured by foliage or non-focal animals. We eliminated 263 interactions from early drought and 118 interactions from late drought which did not meet this criterion. To improve the interpretability of our results, we cleaned our data prior to analysis by removing multimodal postures containing a component observed in fewer than two interactions. After cleaning, we were left with 336 high quality interactions comprising 1,461 multimodal postures for early drought, and 115 interactions comprising 439 multimodal postures for late drought.

References

Ginsberg, J.R. (1988). Social organization and mating strategies of an arid-adapted ungulate: the Grevy’s zebra. [Doctoral dissertation, Princeton University].

Hex, S. B., Rubenstein, D. I. (2024). Using networks to visualize, analyse and interpret multimodal communication. Anim. Behav. 207, 295-317.

Plains zebra time budgets, social behavior, and communication during the 2021-2022 Laikipia-Samburu ecosystem drought

Data files

Abstract

README: Plains zebra time budgets, social behavior, and communication during the 2021-2022 Laikipia-Samburu ecosystem drought

Methods

Works referencing this dataset