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Aim: We test whether geographical variation in the length of appendages in rodent species follows predictions of Allen's rule (a positive relationship between appendage length and temperature) at a broad taxonomic scale (order Rodentia). We also test whether the applicability of this rule varies based on the unit of analysis (species or assemblage), the appendage examined (tail, hind foot, ear), body size, occupied habitat, geographical range size, life mode and saltatorial ability. Location: World‐wide. Time period: Current. Major taxa studied: Rodents (order Rodentia). Methods: We assembled data on the morphology, ecology and phylogeny for ≤ 2,212 rodent species, representing c. 86% of all the described rodent species and c. 95% of the described genera. We tested the predicted Allen's rule associations among size‐corrected appendage lengths and both latitudinal and climatic variables (temperature and precipitation). We applied a cross‐species approach based on phylogenetic regressions and a cross‐assemblage approach based on spatial regressions in equal‐area 1.5° grid cells. Results: Support for Allen's rule was greatest for the tail and was stronger across assemblages than across species. We detected a negative relationship between tail length and (absolute) latitude, which was accounted for by a positive association between tail length and temperature of the coldest month. This association was greatest in desert species. In addition, we observed a negative relationship between ear length and precipitation. Main conclusions: In rodents, Allen's rule is confirmed only for tails, and this association seems to be driven by adaptation to the cold, rather than warm temperatures. Habitat type seems to influence conformity to this rule. Conformity to Allen's rule is likely to be the result of complex evolutionary trade‐offs between temperature regulation and other essential species traits. [ABSTRACT FROM AUTHOR]

Aim: The International Union for Conservation of Nature (IUCN) expert range maps and the Global Biodiversity Information Facility (GBIF) species occurrence data are commonly used to estimate species' geographic range. Macroecological studies often cross‐reference geographic range data with a climate dataset, to extract the mean environmental conditions encountered by a species within its geographic range. We aimed to assess the consistency of the environmental data estimates derived from IUCN versus GBIF geographic range data, and to test whether such differences may affect estimates of ecogeographical relationships, such as Bergmann's rule. Location: Worldwide. Time period: Around 2000. Taxa: Rodents (Rodentia). Methods: We first assessed the correlation between environmental data estimates (19 bioclimatic variables and elevation) derived from IUCN versus GBIF geographic range data of 1,315 rodent species, comparing how range size, conservation status, habitat, zoogeographic realm or elevation changed these correlations. Then, we compared the association between body mass and climate (mean temperature and precipitation) when the latter are derived from IUCN or GBIF data. Results: There was high correlation between environmental data estimates derived from IUCN versus GBIF data, especially when excluding GBIF occurrences outside of IUCN polygons. Species' characteristics, or using the mean or median, did not change the consistency between estimates. Overall, GBIF occurrence data and IUCN range maps produced similar patterns of body mass—climate correlations. Main conclusions: At the large spatial and taxonomic scale employed in this study, there does not seem to be any considerable differences in the average environmental data estimates derived from IUCN versus GBIF geographic range data. This result indicates that both sources of geographic range data could be used independently or in concert for macroecological inferences that involve summarizing species' niches by a single estimate of the average of their used environments. [ABSTRACT FROM AUTHOR]