Energetic cost of locomotor play in pronghorn fawns

Abstract

Play behaviour was studied in pronghorn, Antilocapra americana, at the National Bison Range (Moiese, Montana, U.S.A.). The aim of the study was to make field measurements of the energetic costs of play running. Total daily energy expenditures of fawn were estimated in two different ways: (1) time budget analysis and (2) field metabolic rates based on body weight calculated using a regression equation for herbivorous eutherians. The two methods gave similar estimates. Play occupied 1-2% of total time. Running play constituted on average 2% of total daily energy expenditure and 20% of the daily energy expenditure in excess of resting metabolic rate and growth. A pronghorn fawn that eschewed play and shifted the energy savings into growth could expect to weigh 7% more than a playing fawn by post-natal week 12. © 1991.