The Journal of experimental biology
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In this study we investigate how speed and stride frequency change with body size. We use this information to define 'equivalent speeds' for animals of different size and to explore the factors underlying the six-fold difference in mass-specific energy cost of locomotion between mouse- and horse-sized animals at these speeds. Speeds and stride frequencies within a trot and a gallop were measured on a treadmill in 16 species of wild and domestic quadrupeds, ranging in body size from 30 g mice to 200 kg horses. ⋯ The cost of locomotion is determined primarily by the cost of activating muscles and of generating a unit of force for a unit of time. Our data show that both these costs increase directly with the stride frequency used at equivalent speeds by different-sized animals. The increase in cost per stride with muscles (necessitating higher muscle forces for the same ground reaction force) as stride length increases both in the trot and in the gallop.
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1. Postural behavioural changes during vestibular compensation were studied in goldfish. The tilting posture induced by directional light in the dorsal light reflex (DLR) was monitored by an automated camera system. ⋯ At steady state, the light effect from the operated side had decreased from the high immediately post-ataxic levels to a level roughly 1.5 times normal, but the light effect from the intact side had increased, also reaching a level roughly 1.5 times normal. Thus the final values again show symmetry. 5. Variability appears to be an important feature of the response.