DOI: 10.5061/dryad.s7h44j1k6
title: Data from: Giant mice on small islands: Biogeographic and ecological differences contribute to gigantism in island populations

description: Island populations of small land vertebrates frequently exhibit insular
 gigantism, presenting with larger body sizes compared to their mainland
 counterparts. While insular gigantism has been observed globally, the
 effects of biogeographic and ecological factors on body size in island
 systems are not well understood. Here we examine the biogeographic and
 ecological associations of insular gigantism. Deer Mice (Peromyscus
 maniculatus) were live-trapped, and body mass was measured on six of the
 Gulf Islands and the mainland of British Columbia, Canada. In
 addition to field sampling, body mass measurements were also recovered
 from museum specimens from the Gulf Islands area via the VertNet database.
 Biogeographic measures of land area and island distance from the mainland
 were estimated using ArcMap. The ecological measure of predator species
 richness was estimated from iNaturalist observations. These data were used
 in piecewise structural equation modeling to identify associations with
 insular gigantism. We found evidence of insular gigantism in the Gulf
 Islands system, with island mice having a larger mean body mass than
 mainland populations. Land area was positively associated with predator
 species richness, and predator species richness had a strong negative
 effect on Deer Mouse body mass, resulting in the observed pattern of
 insular gigantism. The concurrent analysis of biogeographic and ecological
 factors contributes to a better understanding of the evolution of insular
 gigantism in small vertebrates and its juxtaposition to the phenomenon of
 insular dwarfism of large vertebrates.
description: # Giant mice on small islands: Biogeographic and ecological differences
 contribute to gigantism in island populations Dataset DOI:
 [10.5061/dryad.s7h44j1k6](10.5061/dryad.s7h44j1k6) ## Description of the
 data and file structure Data was collected as part of a master's
 thesis aimed to understand island gigantism in deer mice. Field data and
 tissue samples were collected from live trapped mice in the Canadian Gulf
 Islands in British Columbia. Museum data was generated from datasets
 publicly available on VertNet.org. ### Files and variables #### File:
 island\_predators.csv **Description:** Information about the predator
 species found on each island ##### Variables * island: Name of the island
 location (or mainland "Vancouver") * unique_species: List of
 unique species derived from iNaturalist data. *No individual records or
 copyrighted materials are included*. * n_species: Count of unique species
 #### File: mean\_depths\_cytB.txt **Description:** Mean sequencing depths
 of the cytB region for samples used in species confirmation analysis #####
 Variables * Column 1: Sample name file path * Column 2: Mean sequencing
 depth #### File: gigantism.fasta **Description:** Fasta file of
 mitochondrial cytB sequences - used to generate phylogenetic tree ####
 File: gigantism.sh **Description:** Outlines code used to generate
 gigantism.fasta #### File: gigantism\_final\_analysis.csv
 **Description:** Dataset generated from field sampled deer mice #####
 Variables * row_field_id: Unique identifier of order samples were
 collected * trapping_code: Unique identifier for each sample (first two
 letters designate sampling location) * sampling_site: Island or mainland
 location where sample was collected * site: Specific site within the
 sampling_site * weight_animal: Mass of animal in grams * distance:
 Distance of the sampling_site from the "mainland" (Vancouver
 Island) in kilometers * islandsize: Area of the sampling_site in square
 kilometers * predation: Predator species richness for sampling_site *
 location: Designation of "mainland" or "island" *
 X_BCAlbers: Longitude coordinate data in BC Albers * Y_BCAlbers: Latitude
 coordinate data in BC Albers * X_UTM10: Longitude coordinate data in UTM10
 * Y_UTM10: Latitude coordinate data in UTM10 #### File: museum\_mice.csv
 **Description:** Data collected from museum specimens generated from
 VertNet.org - *Note: Samples from Lopez Island are not included here as
 they are part of the University of Alaska Museum database designated by a
 CC BY-NC 4.0 license. These data can be found
 at [https://doi.org/10.15468/lbixob](https://doi.org/10.15468/lbixob).*
 ##### Variables * site: Location within the sampling_site where the
 specimen was collected * sampling_site: Island or mainland location where
 the specimen was collected  * lengthinmm: Length of specimen in mm *
 lengthtype: How the length was measured * country: Country where specimen
 was collected * verbatimlocality: Detailed locality information *
 decimallatitude: Latitude in decimals * decimallongitude: Longitude in
 decimals * geodeticdatum: Datum for latitude and longitude data *
 dynamicproperties: Notes on several body measurements of the specimen *
 catalognumber: Dataset catalog number within the institutions dataset *
 sex: Sex of the specimen * lifestage: Lifestage of the specimen *
 eventdate: Date when the specimen was collected * scientificname:
 Scientific Name of the specimen * institutioncode: Institution code
 corresponding to the dataset the observation is from *
 location: Designation of "mainland" or "island" *
 weight_animal: Mass of animal in grams * islandsize: Area of the
 sampling_site in square kilometers * distance: Distance of the
 sampling_site from the closest "mainland" in kilometers *
 predation: Predator species richness for sampling_site #### File:
 gigantism\_script.R **Description:** Code used to run all statistical
 analyses and generate corresponding figures for publication ###
 Code/software I have included the code for the species confirmation
 analysis which was run on a HPC system. The *.sh file runs through the
 commands used and the corresponding software and versions needed. The code
 for statistical analysis and graph making is also included. Run this code
 in R and make sure the `gigantism_final_analysis.csv` and
 `museum_mice.csv` files are in the working directory. ### Access
 information Other publicly accessible locations of the data: * None Data
 was derived from the following sources: * Dataset citation information: 
 Cowan Tetrapod Collection at the University of British Columbia Beaty
 Biodiversity Museum (UBCBBM). University of British Columbia.
  [https://www.gbif.org/dataset/3ad882bb-cd21-4201-8b83-3684bfc6d830](https://www.gbif.org/dataset/3ad882bb-cd21-4201-8b83-3684bfc6d830) (accessed on 2024-12-02) UWBM Mammalogy Collection (Arctos). University of Washington Burke Museum.[https://www.gbif.org/dataset/830eb5d0-f762-11e1-a439-00145eb45e9a](https://www.gbif.org/dataset/830eb5d0-f762-11e1-a439-00145eb45e9a) (accessed on 2024-12-02) * iNaturalist.org. Available from [https://www.inaturalist.org](https://www.inaturalist.org)