Thermoregulation strategies differ for large macropods during high temperatures

As higher temperatures become more frequent due to climate change, thermoregulatory strategies will become increasingly critical survival mechanisms for wild animals. In semi-arid drylands, landscape features such as water and trees can become vital resources for individuals when reducing heat stress. In Australia, such landscapes have witnessed considerable shifts in water availability and widespread canopy loss due to anthropogenic processes, and are subject to greater frequencies of heatwaves and extreme temperatures. We explored the use of dammed watercourses and excavated earth tanks, and tree shade in two large macropod species, eastern grey kangaroos (<i>Macropus giganteus</i>) and red kangaroos (<i>Osphranter rufus</i>) in the semi-arid drylands of south-western Queensland. Using a thermal drone, camera traps, and temperature sensors, we examined the relationship between temperature, water use, and canopy shade use by both species. The likelihood of both species being observed in the sun was negatively correlated with temperature, with the likelihood of observing eastern grey kangaroos in the sun dropping below 50% when temperatures exceeded 28°C, and 17°C for red kangaroos. Probability of detecting kangaroos in the shade was positively correlated with temperature, with red kangaroos more strongly selecting shade than eastern grey kangaroos. For eastern grey kangaroos, we observed greatly increased activity at waterpoints when daily maximum temperatures exceeded 28°C, with a preference for dammed watercourses over excavated earth tanks. Only a weak trend of using dammed watercourses at high temperatures (&gt;36°C) was detected for red kangaroos.<b>Spreadsheets:</b><b>Drone_transects:</b>Spreadsheet containing data from thermal drone transects. 2km long transects with a drone 40m above ground flying at 5m/s, camera angled at 30 degrees.<br>The spreadsheet includes two tabs, one for eastern grey kangaroos and one for red kangaroos, both have the exact same outline/columns.<br>Column information:Transect_ID -&gt; Identifying ID for each transect completedSite -&gt; Name of sites where transects were located (Air, Black_Swan, Westbore_Gate)Month -&gt; Months transects were flownDateTime -&gt; specific date and time of flightsTimeTemperature -&gt; Temperature recorded by iButton sensors at time of flights in CelsiusTotal_x -&gt; Total number of individuals observed on transectx_Sun -&gt; Number of individual counted in the sun for each transectx_Shade -&gt; Number of individual counted in the shade for each transect<b>Kangaroo_waterpoint_activity_vs_Temp:</b>Spreadsheet containing information on kangaroo activity at waterpoints measured from camera traps. Each row represents a single visit or event.Column information:Latitude -&gt; latitude of cameraLongitude -&gt; longitude of cameraStation -&gt; Name of site where camera is locatedCamera -&gt; Camera name/labelDam_type -&gt; Whether waterpoint is tank or dammed watercoursefilenameSpecies -&gt; kangaroo species observed (eastern grey or red)DateTime -&gt; Date and time of eventDateTimeMax_temp -&gt; maximum daily temperature on day of eventMin_temp -&gt; minimum daily temperature on day of eventMean_temp -&gt; mean daily temperature on day of event<br><br><br>