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Objectives and content

The squamate reptiles water loss data base or SquamEWL is the result of a collective effort to compile standard evaporative water loss data of extant squamate reptile species from around the globe, including lizards, snakes and amphisbenians.

The understanding of species responses to global changes, of species adaptations along environmental gradients and of evolutionary radiation in past and present environments calls for global, comprehensive databases of the functional traits of extant species. Resistance to water loss is a critical functional trait that determines importantly species’ responses to climate change through its effects on the water balance of the organism and functional links with energy budget and behavior. In particular, evaporative water loss (EWL) is an important avenue of water loss in many terrestrial or semi-terrestrial animals. Yet, a proper quantification of geographic and phylogenetic variation in EWL requires to control for confounding factors that influence standard measures of whole-organism water loss performed in the laboratory. In this project, we generated a global and validated database of total, respiratory and cutaneous EWL for more than 300 species of squamate reptiles from across the globe.

The current dataset contains more than 2500 sample estimates along with associated errors and comprehensive metadata to allow for meaningful comparisons and statistical analyses of intra- and inter-specific variation in EWL rates. It comes with a program written in R language to check data integrity, compute statistics and produce a uniform dataset of records expressed in the same unit (in mg water per hour) and allows extraction of standard water loss rates (measured for animals at rest under normal low temperature conditions) and filtering data according to their quality.

The database, citation files and meta-data can be downloaded from the Data page where we maintain a permanent, citable and updated version of the data. We plan to update regularly the data source with published and submitted data.

To help us improve the database, please communicate your published articles and send your comments (e.g., requests for correction on the updated datasets) directly to Jean-François Le Galliard. If you want to help us fill the datasets, please use the freely available data template and check all information about the metadata, which are regularly updated on the Data page. Alternatively, you can send us raw unpublished data with a short description of the protocols and all contact details. We will produce a citable database from your datasets and include them in our data.


  • Jean-François Le Galliard, CNRS, France
  • Chloé Chabaud, Université de la Rochelle, PhD student, France
  • François Brischoux, CNRS, France
  • Miguel A. Carretero, CIBIO and Universidade do Porto, Portugal
  • Denis Otávio Vieira de Andrade, Universidade Estadual Paulista – UNESP, Brazil
  • Andréaz Dupoué, Sorbonne Université, Post-doc, France
  • Rodrigo Gavira, CNRS, Post-doc, France
  • Olivier Lourdais, CNRS, France
  • Marco Sannolo, CIBIO and Universidade do Porto, PhD student, Portugal
  • Tom J. M. van Dooren, CNRS, France


Compilation of the database was funded by the Centre National de la Recherche Scientifique (CNRS), the Agence Nationale de la Recherche (Aquatherm: ANR-17-CE02-0013 to JFLG) and a doctoral grant from Ecole normale supérieure to CC.

Authors contribution

Jean-François Le Galliard and Tom van Dooren conceived the project, organized the data collection, and collected and checked data. François Brischoux, Andréaz Dupoué, Rodrigo Gavira and Olivier Lourdais contributed to project conception and helped with data collection and management. Miguel A Carretero, Marco Sannolo and Diego Andrade contributed data and helped with data collection. Chloé Chabaud helped with data collection, data formatting and technical validation.