Giant mice on small islands: Biogeographic and ecological differences contribute to gigantism in island populations

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 wit..., , # 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...,