DOI: 10.5061/dryad.0k6djhbcc
title: Sleeping under pressure: Sleep site selection in urban brown anoles (<em>Anolis sagrei</em>)

description: Daytime microhabitat selection is shaped by both physiological traits and
 environmental pressures, yet nocturnal microhabitat selection remains
 poorly understood in many species. In urban brown anole lizards (Anolis
 sagrei), daytime perch selection is influenced by morphology,
 thermoregulation, and competition, but the factors shaping nocturnal perch
 selection in urban populations are less clear. We examined sleep site
 selection at night in adult male, adult female, and juvenile brown anoles
 in an urban population in New Orleans, Louisiana. Larger individuals
 perched marginally higher than smaller conspecifics, though perch height
 did not differ significantly across groups. Within juveniles, higher body
 temperatures were associated with lower perch heights, a pattern not
 observed in adults. This difference may reflect active thermoregulatory
 behavior on the part of juveniles, or passive heat gain resulting from
 lower thermal inertia. Most lizards slept facing the stem of the plant,
 suggesting a defensive posture toward potential ground-based predators.
 Individuals also slept in dark sleeping perches, with most observed at
 light levels below 1 lx, microhabitats that may reduce predator detection
 or exposure to artificial light at night (ALAN). Overall, sleep site
 selection in this urban population of A. sagrei exhibits marked variation
 within the studied population, and likely reflects the combined influence
 of morphology, light exposure, predation risk, and age-specific
 constraints.
description: # Sleeping under pressure: Sleep site selection in urban brown anoles
 (*Anolis sagrei*) ## Description of the data and file structure These data
 were collected to investigate sleep site selection in an urban population
 of the brown anole lizard (*Anolis sagrei*) in New Orleans, Louisiana.
 Sleeping individuals were located at night and measured for morphology,
 body temperature, perch characteristics, and ambient light levels.
 Morphological traits were included to examine relationships between
 individuals and sleep site use.  Randomly available perches were also
 sampled at the same sites to evaluate whether observed sleep sites
 differed from randomly available habitat. These data accompany the
 published article "Sleeping Under Pressure: Sleep Site Selection in
 Urban Brown Anole Lizards (*Anolis sagrei*)" in Ethology
 (DOI: [https://doi.org/10.1111/eth.70035)](https://doi.org/10.1111/eth.70035) ### Files and variables #### File: random_sampling.csv **Description:** Measurements of randomly available perches sampled at the same urban site as sleeping brown anoles (*Anolis sagrei*) in New Orleans, Louisiana. Each row represents one randomly sampled perch used to characterize habitat availability. ##### Variables * Perch ID: Unique identifier for each randomly sampled perch * perch height_m: Height of the perch above ground (meters) * perch width: Width of the perch (centimeters) * perch length_m: Length of the perch segment (meters) #### File: morphology_perches.csv **Description:** Data collected from individual sleeping brown anole lizards (*Anolis sagrei*) in an urban population in New Orleans, Louisiana. Each row represents a single sleeping individual measured during nocturnal surveys. ##### Variables * ID: Unique identifier for each individual lizard * category: Individual category (adult male, adult female, or juvenile) * tb: Body temperature at the time of observation (°C) * mass: Body mass (grams) * svl: Snout-vent length (millimeters) * head width: Head width (millimeters) * head length: Head length (millimeters) * head depth: Head depth (millimeters) * humerus: Humerus length (millimeters) * radius: Radius length (millimeters) * longest front toe: Length of the longest front toe (millimeters) * femur: Femur length (millimeters) * tibia: Tibia length (millimeters) * longest back toe: Length of the longest back toe (millimeters) * tail length_cm: Tail length (centimeters) * perch height_m: Height of the perch above ground (meters) * perch width: Width or diameter of the perch (centimeters) * perch length_m: Length of the perch segment used by the lizard (meters) * lux: Ambient light intensity at the sleep perch (lux) * position: Body orientation on the perch relative to the stem (toward, away, or perpendicular) #### File: Sleeping_Under_Pressure_Site_Selection.Rmd **Description:** R Markdown script containing all data cleaning, transformation, statistical analyses, and figure generation associated with this study. The script reproduces all results reported in the associated *Ethology* publication. ## Code/software All data files can be viewed using standard spreadsheet software capable of reading CSV files. All statistical analyses and figure generation were conducted in R (version 4.3.1). Analyses were performed using the R Markdown file Sleeping_Under_Pressure_Site_Selection.Rmd, and all required R packages are loaded within the script. Running the R Markdown file in RStudio will reproduce all analyses and figures. ## Access information Other publicly accessible locations of the data: * No additional public repositories host these data. Data was derived from the following sources: * The data were generated by the authors through original field observations and measurements.