Metabolic activity and energy expenditure in primates

Abstract

Hibernation is not a physiologic function that is normally associated with primates, but can perhaps be considered an extreme of the spectrum of metabolic activity and energy expenditure. The perspective that energy expenditure is directly proportional to physical activity may apply across the zoologic record, but has been questioned for primates [1]. Pontzer [1] stated that primates use half the energy of other mammals. Among the factors affecting energy demands, body mass/size is the major overriding determinant of thereutral resting metabolic rate [1]. This holds across mammalian phylogeny, with notable exception of marsupials, edentates, and among primates, strepsirrhines [2,3]. Hypometabolism among Strepsirrhini is greatest for Eulemur fulvus and Lemur catta (69% reduction in basal metabolic rate), Nycticebus coucang (63%), Varecia varecia (70%), Propithecus verrauxi (87%) and least for Galago elegantulus (1.5%), with Lepilemur ruficaudatus, Loris tardigradus, Otolemur crossicaudatus and garnetti and Periodictus potto intermediately reduced at 45% [4]. This contrasts with Haplorhini which is a highly variable suborder. Most approximate anticipated (for their mass) metabolic rate, with the exception of hypometabolism in Aotus triviragautus, Cebuella and Tarsius syrichta. This contrasts with increased basal metabolism in Cercopithicus mitus, Erythrocebus and Macacca fasculatus and fuscata, Saguinus geoffroyi, Papio cynocephalus and Calithix geoffroyi. It is intriguing that the 20% increase in basal metabolic rate in Calithix geoffroyi contrasts with a 30% decrease in C. jacchus decreased 30%. Similarly, basal metabolic rate was as anticipated for weight in Macacca mulatta and Papio papio, in contrast to M. fasculatus, M. fuscata, and Papio cynocephalus.