DOI: 10.5061/dryad.cfxpnvxcg
title: Data from: Active crocodiles are less sociable

description: How animals move and associate with conspecifics is rarely random, with a
 population’s spatial structure forming the foundation on which the social
 behaviours of individuals form. Studies examining the spatial–social
 interface typically measure averaged behavioural differences between
 individuals; however, this neglects the inherent variation present within
 individuals and how it may impact the spatial-social interface. Here, we
 investigated differences in among-individual (co) variance in sociability,
 activity, and site fidelity in a population of wild estuarine crocodiles,
 Crocodylus porosus, across a 10-year period. By monitoring 118 crocodiles
 using coded acoustic transmitters and an array of fixed underwater
 receivers, we discovered that not only did individual crocodiles
 repeatably differed (among-individual variation) in each behaviour
 measured, but also in how consistently they expressed these behaviours
 through time (within-individual variation). As expected, crocodile
 activity and sociability formed a behavioural syndrome, with more active
 individuals being less sociable. Interestingly, we also found that
 individuals that were either more sociable or displayed greater site
 fidelity were also more specialised (lower within individual variation) in
 these behaviours. Together, our results provide important empirical
 evidence for the interplay between spatial, temporal and social
 individual-level behavioural variation and how these contribute to forming
 behavioural niches.
description: # Data from: Active crocodiles are less sociable
 [https://doi.org/10.5061/dryad.cfxpnvxcg](https://doi.org/10.5061/dryad.cfxpnvxcg) We supply the underlying data and R code used in the data analysis and preparation of the manuscript "Active crocodiles are less sociable" which in currently under review in the journal "Philisophical transactions of the Royal Society B". In this study we quantified the degree of among (behavioural phenotypes) and within-individual (behavioural consistency) variation in sociability, daily activity, and site fidelity for a wild population of estuarine crocodiles *Crocodylus porosus*. We investigated whether an individual’s behavioural phenotype correlates with their consistency across consecutive tracking months and whether behaviours were correlated at the among-individual level, thus forming behavioural syndromes. We predicted that crocodiles would display both among- and within-individual variation in spatial and social phenotypes. Specifically, we hypothesised that behavioural phenotypes are correlated with behavioural consistency, with more sociable and site-attached individuals being more consistent through time, while more active individuals would be less consistent. Finally, we predicted that an individual’s degree of sociability would be positively correlated with both their daily activity and degree of site fidelity. ### Author(s) Cameron J. Baker <sup>1,2*</sup>, Barbara Class <sup>3,4</sup>, Ross G. Dwyer <sup>4</sup>, Craig E. Franklin <sup>2</sup>, Hamish A. Campbell <sup>1</sup>, Terri R. Irwin <sup>5</sup>, and Céline H. Frère <sup>2</sup> <sup>1 </sup>Research Institute for Environment & Livelihoods, Charles Darwin University, Darwin, Northern Territory 0815, Australia <sup>2 </sup>The School of the Environment, The University of Queensland, Brisbane, Queensland 4072, Australia <sup>3 </sup>Ludwig-Maximilians-Universität München, 80539 Munich, Germany <sup>4 </sup>School of Science, Technology and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland 4556, Australia <sup>5 </sup>Australia Zoo, Steve Irwin Way, Beerwah 4519, Queensland, Australia   <sup>*</sup>Corresponding author: [cameron.baker@cdu.edu.au](mailto:cameron.baker@cdu.edu.au) ## Description of the data and file structure ### File list Acoustic_telemetry_data.csv Behavioural_metrics.csv Crocodile_metrics.csv Data_analysis.R CompDHGLM.rds ### File descriptions Acoustic_telemetry_data.csv - A data frame containing the raw acoustic telemetry data underlying the analysis presented in the manuscript. * DATETIME: The date and time that an acoustic transmitter was detected at a specific acoustic hydrophone * TRANSMITTERID:  The unique identity of each crocodile * SENSOR1: The either a temperature or depth recording if a transmitter has that functionality * UNITS1: The units of the sensor recording from the transmitter * STATIONNAME: The name of the acoustic hydrophone station that a transmitter was detected at Behavioural_metrics.csv - A data frame containing the processed crocodile behavioural metrics used in the analysis presented in the manuscript. * TRANSMITTERID: The unique identity of each crocodile * Unique_months: The unique year/month combination for each observed value * Year: The year a value was observed * Month: The month a value was observed * Number_associates: The number of tagged conspecifics that a focal individual was observed co-occurring at acoustic hydrophones within a particular month * Potential_associates: The number of tagged conspecifics detected within the focal individual's social environment. For this study, an individuals social environment was determined as the set of acoustic hydrophones a focal individual was observed within the specific month * Prop_associations: The proportion of conspecifics an individual was observed associating with (observed associates) over the number of individuals present within their social environment (potential associates) per month. This is the measure of sociability used in the study * Sex: The sex of the focal crocodile * Mean_TL: The total length of the focal crocodile. For individuals that were captured across multiple years, their mean total length is used * Distance: The mean river distance (km) travelled by the focal individual per day. This is the measure of activity used in the study * Area95: The total area (km<sup>2</sup>) of the focal individuals' least cost utilisation distribution (lcUD). * Overlaps: The volume of intersection (VI) between a focal individual's lcUD for the current month and the preceding month. This is the measure of site fidelity used in the study * Detections: The number of times the focal individual was detected within the acoustic hydrophone array. * cubed_associates: Prop_associations that has been cube-root transformed to normalise the data for modelling * cubed_distance: Distance that has been cube-root transformed to normalise the data for modelling * scale_cube_associates: Cubed_associates that have been standardised for modelling (mean = 0, SD = 1) * scale_cube_distance: Cubed_distance that have been standardised for modelling (mean = 0, SD = 1) * scale_mean_TL: Mean_TL that have been standardised for modelling (mean = 0, SD = 1) Crocodile_metrics.csv - A data frame containing the identity of each tagged crocodiles, along with their sex and total length (TL) * TRANSMITTERID: The unique identity of each crocodile * Sex: The sex of the focal crocodile * Mean_TL: The total length of the focal crocodile. For individuals that were captured across multiple years, their mean total length is used Missing values are denoted by NA. Data_analysis.R - A detailed account of the model fitting and downstream analysis presented in the manuscript, along with all the code required to generate each of the figures. It relies on the data objects Behavioural_metrics.csv and Crocodile_metrics.csv as inputs. The code produces a model output which is also provided as CompDHGLM_all_crocs.rds. CompDHGLM_all_crocs.rds - The model output produced from Data_analysis.R Please contact the project contributors with any questions or comments regarding the analyses. ## Sharing/Access information The code required to determine the behaviours of interest (sociability, activity, site fidelity) is available from the below locations: [https://github.com/Cameron-J-Baker/Supporting-code-Baker_et-al](https://github.com/Cameron-J-Baker/Supporting-code-Baker_et-al): Determining crocodile home range and space use [https://github.com/Cameron-J-Baker/Baker_et_al_2023_Ani_Behav](https://github.com/Cameron-J-Baker/Baker_et_al_2023_Ani_Behav): Determining associations between crocodiles ## Code/Software All analyses were completed using R 4.1.0.