Abstract
BackgroundMovement is the major contributor to active energy expenditure in most vertebrates and it is regularly characterised by body acceleration that can be captured by animal-attached accelerometers (ACC). Overall dynamic body acceleration (ODBA) is a metric derived from ACC data, which can be used as a proxy for energy expenditure over fine time scales. MethodsHere, we used ACC and GPS data collected from free-ranging dingoes in central Australia to investigate their activity-specific energetics, and activity patterns through time and space. We classified dingo activity into stationary, walking, and running behaviours, and estimated daily energy expenditure via activity-specific time-energy budgets. We tested whether dingoes behaviourally thermoregulate by modelling ODBA as a function of ambient temperature (Ta) during the day and night. We used traditional distance measurements (GPS) as well as fine-scale activity (ODBA) data to assess their daily movement patterns.ResultsWe retrieved ACC and GPS data from seven dingoes. Their mass-specific daily energy expenditure was significantly lower in summer (288 kJ kg-1 day-1) than winter (495 kJ kg-1 day-1; p = 0.03). Overall, dingoes were much less active during summer where 91% of their day was spent stationary in contrast to just 46% during winter. There was a sharp decrease in ODBA with increasing ambient temperature during the day (R2 = 0.59), whereas ODBA increased with increasing Ta at night (R2 = 0.39). Distance and ODBA were positively correlated (R = 0.65) and produced similar crepuscular patterns of activity.ConclusionOur results indicated solar radiation and ambient temperature drove the behaviour of dingoes. Seasonal differences of daily energy expenditure (DEE) in free-ranging eutherian mammals have been found in several species, though this was the first time it has been observed in a wild canid. The negative relationship between dingo activity (ODBA) and Ta during the day implies that high heat gain from solar radiation is a factor limiting diurnal dingo activity in an arid environment.
Counting calories in cormorants: dynamic body acceleration predicts daily energy expenditure measured in pelagic cormorants
