DOI: 10.5061/dryad.djh9w0w92
title: Data and code from: Controlled hyperthermia by flying-foxes in the wild: Understanding mammalian tolerance to hotter summer conditions

description: Extreme heat events increasingly challenge the thermoregulatory capacities
 of wildlife, as the frequency, intensity, and duration of these events
 rise under anthropogenic climate change. Biologging can reveal the
 physiological and behavioural responses of wild animals to natural
 variation in environmental conditions, but few studies have recorded
 thermoregulatory patterns during extreme heat events. Flying-foxes
 (Pteropus spp.) are convenient bioindicators of the impacts of extreme
 heat events on wildlife because they roost in exposed colonies in trees
 where population-level consequences, including mass mortalities, can be
 readily observed. To understand how flying-foxes regulate their body
 temperature (Tb) in response to extreme heat in the wild, we used
 implanted temperature-sensitive transmitters to record the core body
 temperature of 17 adult male grey-headed flying-foxes (Pteropus
 poliocephalus) on 142 different days across two Austral summers, including
 6 days when air temperature (Ta) exceeded 42 °C and thousands of
 flying-foxes died. Focal individuals exhibited marked daily heterothermy,
 with generally a decrease in Tb shortly after dawn (minimum: 35.9 ± 0.1
 °C; absolute: 31.1 °C) followed by an increase during the day (maximum:
 38.7 ± 0.2 °C; absolute: 44.3 °C). Above Ta of 29.5 °C, bats allowed Tb to
 rise above normal levels (i.e., controlled hyperthermia). On extreme heat
 days (Ta &gt; 42 °C), Tb increased by up to 6 °C to a daily maxima of
 40.5 to 42.4 °C, so that Ta exceeded Tb on average at &gt; 40.0 °C,
 2.5 °C higher than without controlled hyperthermia. Large variation in Tb,
 as exhibited by adult male grey-headed flying-foxes, reduces the
 physiological costs of exposure to wide-ranging thermal conditions in
 summer. Controlled hyperthermia during extreme heat events increases the
 scope of Ta allowing non-evaporative heat loss and hence decreases water
 loss during these potentially lethal conditions. The ability to manage
 elevated Tb and high rates of evaporative water loss will shape the
 resilience of many species to future hot weather events.
description: We used temperature-sensitive telemetry to record the
 T<sub>b</sub> of adult male grey-headed flying-foxes,
 <em>Pteropus poliocephalus</em>, while they were roosting
 during summer at a roost camp in Adelaide, South Australia.
 We obtained weather data at 1-minute resolution, including air
 temperature (°C), relative humidity (%), and wind speed (km/h), by
 averaging between two Australian Bureau of Meteorology weather stations,
 located 2.9 km west (station #023000) and 1.3 km south-east (station
 #023090) of the roost site. Bureau of Meteorology data are not provided in
 this dataset submission.
description: # Data and code from: Controlled hyperthermia by flying-foxes in the wild:
 Understanding mammalian tolerance to hotter summer conditions
 [https://doi.org/10.5061/dryad.djh9w0w92](https://doi.org/10.5061/dryad.djh9w0w92) ## Description of the data and file structure We have submitted our raw data and code for research entitled "Controlled hyperthermia by flying-foxes in the wild: understanding mammalian tolerance to hotter summer conditions" by Melissa J. Walker, Justin A. Welbergen, Jessica Meade, Wayne S. J. Boardman, Terry Reardon, John M. Martin, Adam McKeown, and Christopher Turbill. Body temperature data [tb_data.csv] was collected by Walker, Turbill, Reardon, Boardman, Martin, and McKeown from grey-headed flying-foxes at a day-roosting site in Adelaide Botanic Park, South Australia. Body temperatures were derived from pulse intervals of temperature-sensitive radio transmitters implanted in each bat, with data captured manually using handheld receivers and a stopwatch, or by receiver stations positioned within the roosting camp. Measurements were collected when bats were manually radio tracked or were located within roughly 200 m of receiver stations.  Weather data at 1-minute resolution, including air temperature (°C), relative humidity (%), and wind speed (km/h), were obtained by averaging between two Australian Bureau of Meteorology (BoM) weather stations, located 2.9 km west (station #023000) and 1.3 km south-east (station #023090) of the roost site. This data were purchased and are not provided in this dataset submission (in File: tb_data.csv the following variables appear blank: air_temperature_degreesC, relative_humidity_percent, wind_speed_km_h). R Code / Script [R Code \_ Walker et al] written by Walker.  ### Files and variables #### File: tb_data.csv **Description:** Body temperature data [tb_data.csv] was collected by Walker, Turbill, Reardon, Boardman, Martin, and McKeown from grey-headed flying-foxes at a day-roosting site in Adelaide Botanic Park, South Australia.  ##### Variables * datetime_ACST_DLS: Date and time of each body temperature measurement (body_temperature_degreesC) in Australian Central Standard Time  * id_number: Individual identification number for each bat * body_temperature_degreesC: Core body temperature in degrees Celsius, determined using pulse intervals from temperature-sensitive radio transmitters implanted in each bat  * data_source_body_temperature: A factor that denotes whether body temperature (body_temperature_degreesC) was collected by an autonomous logger "logger" or manually "manual" using a handheld receiver and stopwatch.  * air_temperature_degreesC: Air temperature in degrees Celsius [BoM - intentionally redacted] * relative_humidity_percent: Relative humidity in percent [BoM - intentionally redacted] * wind_speed_km_h: Wind speed in kilometres per hour [BoM - intentionally redacted] * sunriseACST: Time of sunrise calculated for the city of Adelaide South Australia in Australian Central Standard Time  * sunsetACST: Time of sunset calculated for the city of Adelaide South Australia in Australian Central Standard Time  * day.night: a factor that denotes phase (day/rest phase OR night/active phase) that body temperature (body_temperature_degreesC) was collected; d = day, n = night.  ## Code/software R Code / Script [R_Code__Walker_et_al.txt] written by Walker.