The 84th Annual Meeting of the American Association of Physical Anthropologists (2015)


Do longer limbs translate into a reduced cost of transport? A study of locomotor performance and gait in the Longshanks mouse

LEAH SPARROW1 and CAMPBELL ROLIAN2.

1Department of Veterinary Medical Sciences, University of Calgary, 2Department of Comparative Biology and Experimental Medicine, University of Calgary

March 27, 2015 11:00, Grand Ballroom A/B Add to calendar

Primates must travel in order to acquire the resources necessary to support life. Traits that improve locomotor performance, for example by reducing the energetic cost of ranging, may lead to a larger net energy intake, and thus may be favored by natural selection. One such trait is limb length: Previous functional studies, mostly among species, have shown a negative relationship between limb length and the energetic cost of transport (COT). However, the potential confounding effects of intra- and interspecific variation in other anatomical and behavioral factors in these studies make this relationship less straightforward. We investigated this relationship in the Longshanks mouse, a unique line selectively bred for increased relative tibial length. The Longshanks mouse has on average 13% longer tibia relative to body mass compared to a random-bred control cohort. We tested the hypothesis that the Longshank mouse would have a lower COT, mediated in part by increased stride length. Longshanks (N=22) and control mice (N=23) ran on a metabolic treadmill at three different speeds while oxygen consumption was monitored. The same mice also ran on a treadmill for gait analysis, which provided gait parameters including stride frequency and stride length. Results show that COT is reduced by ~8-10% in Longshanks vs control mice. In addition, Longshank mice had increased stride length (+7-9%) and lower stride frequency (-6-8%). These data confirm the relationship between limb length and locomotor performance within quadrupedal species, with implications for the evolution of limb length diversity in primates.

This work was funded by a Queen Elizabeth II Scholarship to LS, NSERC Discovery Grant 4181932 to CR, and the Faculty of Veterinary Medicine at the University of Calgary.