Gloger's rule or historical conjecture? Tests in mammals

Gloger’s rule states that homeotherms are darker at lower latitudes; however, a number of 19th-century naturalists also suggested that animals are more brightly coloured in the tropics than in temperate regions. Using phylogenetic comparative methods, we investigated and compared both ideas across a global sample of 2,726 species of mammals, examining their head, torso, legs, and tail regions. Coloration data were obtained from photographs and compared with a colour chart specifically devised for mammals; ecological data were extracted from pre-existing, open-source databases. All analyses were conducted using phylogenetic comparative generalised linear mixed models in a Bayesian framework. We found strong support for mammals being darker in the tropics and in areas of high precipitation and evapotranspiration, little support for them being darker in warmer areas, little support for them being redder in more arid regions (a more nuanced interpretation of Gloger’s rule), and virtually no..., , , # Ecogeographical Rules

[https://doi.org/10.5061/dryad.2bvq83c04](https://doi.org/10.5061/dryad.2bvq83c04)

The Excel dataset GvHC_Data_040725.csv contains taxonomic information for 4,411 extant, wild, terrestrial, non-volant mammal species, followed by colour trait data and ecological trait data.

Colour traits are split into four distinct regions of the body: head, torso, legs, and tail.

* Primary and all secondary colour scores were generated through comparison of photographs of each species to a mammal pelage melanisation chart
* Numbers of colours is a simple count of the amount of distinct colour scores that were present on each body region of each species
* Colour contrast of a body region was determined through comparison of the first- and second-most prevalent colours upon each body region

- Body region pattern scores were split into discrete categories

Ecological trait data were collated from the existing database PanTHERIA, and consist of:

* Mean annual temperature value...,