DOI: 10.5061/dryad.3n5tb2rq5
title: Data from: Social networks reveal sex- and age-patterned social structure in Butler’s Gartersnakes

description: Sex- and age-based social structures have been well-documented in animals
 with visible aggregations. However, very little is known about the social
 structures of snakes. This is most likely because snakes are often
 considered non-social animals and are particularly difficult to observe in
 the wild. Here, we show that wild Butler’s Gartersnakes have an age and
 sex assorted social structure similar to more commonly studied social
 animals. To demonstrate this, we use data from a 12-year
 capture-mark-recapture study to identify social interactions using social
 network analyses. We find that the social structures of Butler’s
 Gartersnakes comprise sex- and age-assorted intra-species communities with
 older females often central and age segregation partially due to patterns
 of study site use. In addition, we find that females tended to increase in
 sociability as they aged while the opposite occurred in males. We also
 present evidence that social interaction may provide fitness benefits,
 where snakes that were part of a social network were more likely to have
 improved body condition. We demonstrate that conventional capture data can
 reveal valuable information on social structures in cryptic species. This
 is particularly valuable as research has consistently demonstrated that
 understanding social structure is important for conservation efforts.
 Additionally, research on the social patterns of animals without obvious
 social groups provides valuable insight into the evolution of group
 living.
description: We examined the influence of sex, age, and body condition on
 social patterns in Butler’s gartersnakes. We did so with data from a
 long-term capture-mark-recapture project monitoring a population of snakes
 under threat from a road construction project. Coverboards were primarily
 used to locate the snakes across a ~2 ha area with 3 major sampling sites.
 The sex, weight, and snout-vent length (SVL) of the snakes were recorded
 at the time of capture as well as the sampling site, the exact location,
 and the time. Body condition was defined by the scaled mass index which is
 derived from weight and SVL. Weight was used as a proxy for age. Social
 networks were constructed from the capture time and location data, and we
 modeled the relationship between demographic factors, weighted degree, and
 community betweenness. To derive community betweenness, we subdivided our
 networks into communities of individuals who tended to associate with each
 other and calculated the betweenness of the individuals within these
 communities. We additionally examined sex and age homophily as well as the
 order of arrival of dyads that shared a capture location. Below, we
 outline how we used these data to construct social networks and how we
 then analyzed the resulting data set. The social
 networks were constructed based on the temporal and physical proximity of
 the snakes at the time of capture. In the resulting networks, the edges
 represent the probability of an association occurring. As such, a 1
 indicates that two snakes were found at the same place and the same time.
 A value less than 1 indicates that the snakes were found further apart
 (temporally and/or physically). We constructed networks at different
 scales of proximity. We identify these as the precise and three
 broad-scale networks. The precise network is derived only from direct
 associations. The broad-scale networks expand the possible temporal and
 physical proximity allowances to include possible associations within 14,
 10, or 5 days. The analysis was done with R v4.2.1. We
 tested for non-random associations using null models that controlled for
 temporal and physical space use. To test for intra-species communities, we
 used a Louvain partition and tested the robustness of the resulting
 communities compared to communities generated from random graphs using
 the <em>robin</em> package. To test for relationships between
 phenotypes and network measures, we used mixed-effect hurdle models with
 node-label permutations.  We tested the inherent type I error rates of
 these models by simulating the same analyses but with randomly generated
 values for our independent variables. We derived homophily values from the
 networks using the<em> igraph</em> package and tested them
 against values derived from permutated graphs. To examine the order of
 arrival in shared space, we designated snakes as leaders and followers
 based on their order of capture at the same location - with leaders
 captured first. We then used a multi-membership model constructed with
 the<em> brms</em> package to examine the relationship between
 sex and age on the order of arrival. More details on these analyses are
 available in the manuscript and/or by request.
description: **Social Networks Reveal Sex- and Age-Patterned Social Structure in
 Butler’s Gartersnakes**
 [https://doi.org/10.5061/dryad.3n5tb2rq5](https://doi.org/10.5061/dryad.3n5tb2rq5) These data can be used to recreate the analyses presented in the manuscript. They are the result of information collected during a 12-year capture-mark-recapture project done on Butler's gartersnakes in Ontario Canada, as well as the social networks derived from the capture locations of the snakes. As Butler's gartersnakes are endangered in Ontario, it was a requirement that we anonymize the capture locations. **Description of the data and file structure** Five files have been made available for reproducing the analyses found in the manuscript. Data key file: The Excel file entitled Data Key contains summaries of the other data files and the information needed to understand the variables and their labeling. Two Adjacency matrices files: Two of the files contain the adjacency matrices derived from the social networks described in the manuscript. The social networks were constructed based on the snakes' capture location and date of capture. The intersection of a row and a column in these adjacency matrices represents the probability of an association occurring between two snakes with a 1 indicating that they were found at the same place and the same time. A value less than 1 indicates that the snakes were found further apart (temporally and/or physically). The precise network (AdjacencyMatrixPrecise.xlsx) is an adjacency matrix derived only from direct associations. The AdjacencyMatrixBroad Excel file contains the adjacency matrices for the broad-scale analyses with each workbook containing a separate matrix. The difference between the matrices is the time scale with which there is a minimum probability of interaction between any two snakes (14 days, 10 days or 5 days). General data file: The Excel file titled GarterSnakeSocialStructure contains the raw data collected from the snakes at the time of capture such as sex, weight, and anonymized capture site. This file also contains the social network measures used in the analyses. Details regarding each variable can be found in the Data Key Excel file. The second workbook in this file contains the broad-scale network data shown as dyads. Within the dyads, snakes were designated leaders if they occupied shared space first. Zipped file: The zipped file contains two files. One file is the R code for the type 1 error rate simulations done in the manuscript. There is extensive documentation at the start of the R script that will assist in understanding and using this R code. The second file is the data used in the R script. It is similar to the general data file but contains only the information necessary for the simulations. The independent variables in the file are generated randomly and randomly sampled for the type 1 error simulations. The following is a data key for the randomIVdata.rds data file: | Variable name | Description | | ------------- | ----------- | | id | The unique identification number used for each snake | | sex | sex of the snake. As this independent variable is randomly generated and sampled for this analysis, the values corresponding to 1 and 0 are arbitrary. | | weight | Weight. As this independent variable is randomly generated and sampled for this analysis the units are not meaningful. | | SMI.rob | Robust version of the scaled mass index. See Peig & Green 2009 (https://doi.org/10.1111/j.1600-0706.2009.17643.x) for the calculation involved. As this independent variable is randomly generated and sampled for this analysis the units are not meaningful. | | ny | The number of years that the snake was captured within any network. | | soc\_14 | Association index for the broad scale network with 14-days 50-meter thresholds | | soc\_10 | Association index for the broad scale network with 10-days 50-meter thresholds | | soc\_5 | Association index for the broad scale network with 5-days 50-meter thresholds | | soc\_0 | Association index for the precise scale network | | bin\_soc\_14 | Binary association index for a logistic regression analysis. Snakes that are part of the broadest scale network (14-day 50-meter threshold) have a 1 value. Snakes that are not part of the network have a 0. | | bin\_soc\_10 | Binary association index for a logistic regression analysis. Snakes that are part of the 10-day 50-meter (thresholds) broad scale network have a 1 value. Snakes that are not part of this network have a 0. | | bin\_soc\_5 | Binary association index a logistic regression analysis. Snakes that are part of the 5-day 50-meter (thresholds) broad scale network have a 1 value. Snakes that are not part of this network have a 0. | | bin\_soc\_0 | Binary association index the precise scale (found on the same day at the same time) logistic regression analysis. Snakes that are part of the precise network have a 1 value. Snakes that are not part of the network have a 0. | | btwn14 | betweenness value for an individual within their community at the broad scale level of analysis with a 14-day 50-meter threshold. Snakes that are not part of a community have an NA value. | | btwn10 | betweenness value for an individual within their community at the broad scale level of analysis with a 10-day 50-meter threshold. Snakes that are not part of a community have an NA value. | | btwn5 | betweenness value for an individual within their community at the broad scale level of analysis with a 5-day 50-meter threshold. Snakes that are not part of a community have an NA value. | | btwn0 | betweenness value for an individual within their community at the precise scale level of analysis. Snakes that are not part of a community have an NA value. | | bin\_btwn\_14 | Binary association index for a logistic regression analysis. Snakes that have a betweenness score at the broadest scale network (14-day 50-meter threshold) have a 1 value. Snakes that do not have a betweenness score have a value of 0. Snakes that are not part of a community have an NA value. | | bin\_btwn\_10 | Binary association index for a logistic regression analysis. Snakes that have a betweenness score at the 10-day 50-meter (threshold) broad scale network have a 1 value. Snakes that do not have a betweenness score have a value of 0. Snakes that are not part of a community at this threshold have an NA value. | | bin\_btwn\_5 | Binary association index for a logistic regression analysis. Snakes that have a betweenness score at the 5-day 50-meter (threshold) broad scale network have a 1 value. Snakes that do not have a betweenness score have a value of 0. Snakes that are not part of a community at this threshold have an NA value. | | bin\_btwn\_0 | Binary association index for the precise scale (found on the same day at the same time) community betweenness logistic regression analysis. Snakes that have a betweenness score in the precise network have a 1 value. Snakes that do not have a betweenness score have a value of 0. Snakes that are not part of a community at this threshold have an NA value. | | yrzone | A grouping variable for random sampling. This was generated by combining the sampling zone with the year of capture and then converting the resulting values into their respective factor levels.   |