Functional Measurement of Hind-Foot Reversal in Family Sciuridae

Shelley A. Etnier*

*Butler University, Indianapolis, IN 46208.

Northeastern Naturalist, Volume 32, Issue 2 (2025): 197–209

First published early online: 10 May 2025

Abstract
Many arboreal mammals use hind-foot reversal (HFR) during headfirst descent from trees. HFR occurs when the extended hind limb plantarflexes and supinates such that the plantar surface can contact the support while the digits point skyward. In this study, I quantified HFR in 5 sciurid species that varied in their level of arboreality: Sciurus carolinensis (Gray Squirrel), S. niger (Fox Squirrel), Tamias striatus (Eastern Chipmunk), Cynomys parvidens (Prairie Dog), and Marmota monax (Woodchuck). Arboreal specialists exhibited significantly more plantarflexion and supination relative to species that are more terrestrial. Semi-arboreal species exhibited intermediate values, suggesting that incomplete HFR may be beneficial for species that navigate both on the ground and in the trees.

Download Full-text pdf (Accessible only to subscribers. To subscribe click here.)