Energetics of running and post-exercise oxygen consumption in Ctenomys talarum: digging adaptations have an effect?

Abstract

The fossorial rodent Ctenomys talarum faces conflicting mechanical and energetic demands due to its digging-specialized morphology and reliance on surface foraging. To evaluate how these demands affect locomotor performance, we investigated the energetics of surface running in this species. Specifically, we assessed whether its anatomy increases metabolic cost, limits post-exercise recovery, and influences the net cost of transport (NCOT). Metabolic rate was measured while animals ran at different speeds on a treadmill, and excess post-exercise oxygen consumption (EPOC) was quantified during recovery. The metabolic rate increased linearly with speed, whereas stride frequency increased with speed up to a breakpoint at 0.56 m/s, which coincided with a gait transition, suggesting biomechanical constraints on speed scaling. The NCOT by running did not differ significantly from allometric predictions for similar sized terrestrial mammals, indicating that digging adaptations do not raise the cost of running. However, when recovery is included, total energetic cost increased markedly. This supports the idea that EPOC imposes a high energetic burden. Thus, although C. talarum runs with comparable efficiency to surface-dwelling species, the combination of elevated recovery cost and mechanical constraint may limit the overall terrestrial performance. These physiological trade-offs may shape key aspects of the behavior and ecology of C. talarum, including foraging strategies, predator avoidance, and dispersal capacity in natural environments.