Estimates of the energetic costs of locomotion (COL) at different activity levels are necessary to answer fundamental eco-physiological questions and to understand the impacts of anthropogenic disturbance to marine mammals. We combined estimates of energetic costs derived from breath-by-breath respirometry with measurements of overall dynamic body acceleration (ODBA) from biologging tags to validate ODBA as a proxy for COL in trained common bottlenose dolphins (Tursiops truncatus). We measured resting metabolic rate (RMR); mean individual RMR was 0.71–1.42 times that of a similarly sized terrestrial mammal and agreed with past measurements that used breath-by-breath and flow-through respirometry. We also measured energy expenditure during submerged swim trials, at primarily moderate exercise levels. We subtracted RMR to obtain COL, and normalized COL by body size to incorporate individual swimming efficiencies. We found both mass-specific energy expenditure and mass-specific COL were linearly related with ODBA. Measurements of activity level and cost of transport (the energy required to move a given distance) improve understanding of the COL in marine mammals. The strength of the correlation between ODBA and COL varied among individuals, but the overall relationship can be used at a broad scale to estimate the energetic costs of disturbance and daily locomotion costs to build energy budgets, and investigate the costs of diving in free-ranging animals where bio-logging data are available. We propose that a similar approach could be applied to other cetacean species.

These data were generated to investigate the energetic cost of locomotion in common bottlenose dolphins (Tursiops truncatus). We quantified energy expenditure (i.e., metabolic rate) by measuring oxygen consumption via a pneumotachometer (a breath-by-breath respirometry device). The dolphins breathed into the pneumotachometer while at station (stationary next to the side of the lagoon). We integrated flow rate (milliliters per second) and oxygen concentration (%) to obtain oxygen consumption rate. We measured resting metabolic rate (RMR) for several minutes before a swim trial. We then asked the dolphins to swim multiple laps, breathing into the pneumotachometer several times at station in between each lap. The dolphins were post-prandial (i.e., no food consumed for > 12 hrs) during all measurements. 

The dolphins also wore a suction-cup-attached tag (which included a trial-axial accelerometer), placed dorsally mid-way between the blowhole and the dorsal fin. We calculated mean overall dynamic body acceleration (ODBA) from the accelerometer signals. ODBA gave us a proxy for how active the dolphins were during a trial, to compare with energy expenditure measured via respirometry.

Please refer to the README file, and to the manuscript Allen et al., (2022), Dynamic body acceleration as a proxy to predict the cost of locomotion in bottlenose dolphins, The Journal of Experimental Biology.