The Influence of Snow Properties on Speed and Gait Choice in the Svalbard Rock Ptarmigan ( Lagopus muta hyperborea )

• Published in: Integrative Organismal Biology
• Main Authors: Mármol-Guijarro, A, Nudds, R, Folkow, L, Sellers, W, Falkingham, P, Codd, J
• Other Authors: Secretaría Nacional de Educación Superior Ciencia, Tecnología e Innovacíon del Ecuador, Biotechnology and Biological Sciences Research Council
• Format: Article in Journal/Newspaper
• Language: English
• Published: Oxford University Press (OUP) 2021
• Subjects: Plant Science; Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Svalbard; Lagopus muta; Lagopus muta hyperborea; rock ptarmigan; Svalbard Rock Ptarmigan
• Online Access: http://dx.doi.org/10.1093/iob/obab021; http://academic.oup.com/iob/advance-article-pdf/doi/10.1093/iob/obab021/38896049/obab021.pdf; http://academic.oup.com/iob/article-pdf/3/1/obab021/40082571/obab021.pdf

Synopsis Substrate supportiveness is linked to the metabolic cost of locomotion, as it influences the depth to which the foot of a moving animal will sink. As track depth increases, animals typically reduce their speed to minimize any potential energetic imbalance. Here, we examine how self-selected speed in the Svalbard rock ptarmigan is affected by snow supportiveness and subsequent footprint depth measured using thin-blade penetrometry and 3D photogrammetry, respectively. Our findings indicate that snow supportiveness and footprint depth are poor predictors of speed (r2 = 0.149) and stride length (r2 = 0.106). The ptarmigan in our study rarely sunk to depths beyond the intertarsal joint, regardless of the speed, suggesting that at this relatively shallow depth any increased cost is manageable. 3D reconstructions also indicate that the ptarmigan may exploit the compressive nature of snow to generate thrust during stance, as a trend toward greater foot rotations in deeper footprints was found. It remains unclear whether the Svalbard ptarmigan are deliberately avoiding unsupportive snowy substrates. However, if they do, these results would be consistent with the idea that animals should choose routes that minimize energy costs of locomotion.