Data from: Mechanical evidence that flamingos can support their body on one leg with little active muscular force

Flamingos (Phoenicopteridae) often stand and sleep on one leg for long periods, but it is unknown how much active muscle contractile force they use for the mechanical demands of standing on one leg: bodyweight support and maintaining balance. First, we demonstrated that flamingo cadavers could passively support bodyweight on one leg without any muscle activity while adopting a stable, unchanging, joint posture resembling that seen in live flamingos. In contrast, the cadaveric flamingo could not be stably held in a two-legged pose, suggesting a greater necessity for active muscle force to stabilize two-legged vs. one-legged postures. Our results suggest flamingos engage a passively engaged gravitational stay apparatus (proximally located) for weight support during one-legged standing. Second, we discovered live flamingos standing on one leg have markedly reduced body sway during quiescent vs. alert behaviors, with the point of force application directly under the distal joint, reducing the need for muscular joint torque. Taken together, our results highlight the possibility that flamingos stand for long durations on one leg without exacting high muscular forces and, thus, little energetic expenditure.