Effects of Weather Conditions in Summer on the Maintenance Behavior of Western Grey Kangaroos, Macropus-Fuliginosus

Abstract

The behaviour of seven western grey kangaroos was observed, in a 0.2 ha paddock of annual pasture over nine days on which the daily maximum temperature ranged from 22°C to 42°C. Grazing, standing and lying activities and use of shade were recorded. Regression and fourier analyses were used to relate behavioural measurements to environmental conditions. Cyclic patterns of grazing and lying closely followed those of ambient and radiant temperatures. When maximum radiant and ambient temperatures were higher, grazing began later in the evening and ceased earlier in the morning. Grazing time decreased as daytime radiation and relative humidity rose. With increasing heat load, animals lay down more during the day; the radiant temperature in the sun between 0600 and 0900 h determined when they first lay down while radiant temperature in the shade determined when animals moved to shade. Environmental conditions did not greatly influence the time spent standing, but animals stood for more of their resting time with increased daytime humidity. Individuals differed in the mean times spent on major activities, but not in the timing of these activities or the use of shade.