Meeting Abstract
Foraging by large (> 25 kg), mammalian carnivores often entails cryptic tactics to surreptitiously locate and overcome highly mobile prey. Many forms of unsteady locomotion from stroke-and-glide maneuvers by marine mammals to sneak-and-pounce behaviors by terrestrial canids, ursids and felids are involved. While affording proximity to vigilant prey, these tactics are also associated with unique energetic costs and benefits to the predator. Here we examine the energetic consequences of interrupted locomotion in mammalian carnivores and assess the role of these behaviors in overall foraging efficiency. Behaviorally-linked 3-axis accelerometers were calibrated to provide instantaneous energetics from Overall Dynamic Body Acceleration (ODBA), as well as the cost per stroke or step in marine and terrestrial mammals, respectively. The instruments were deployed on wild adult Weddell seals (Leptonychotes weddellii) and mountain lions (Puma concolor), and compared to previously published values for other carnivores. We found that intermittent locomotion resulted in significant energetic savings for both aquatic and terrestrial hunters. The cost of a foraging dive by the seals decreased 9.2 to 59.6% depending on the proportion of time gliding. Similarly, hunting costs in mountain lions was reduced by >40% by changing from constant movement to sneak attacks. These energetic savings help to mitigate the comparatively high field metabolic rate (FMR, kJ.day-1) of large carnivores, where FMRmarine carnivore, wild canids = 1367.7mass0.76 (n = 26 species, r2 = 0.95, p<0.001), and demonstrate the importance of locomotor versatility in highly active predators. (Supported by the Office of Naval Research and NSF -Polar Programs and IDBR.)
