INTRODUCTION

The study of how animals apportion their time and energy (energetics) can provide much insight into physiology, ecology and evolution (Bartholomew, 1982; Schmidt-Nielsen, 1997). Body temperature has a profound effect on the ability of animals to function effectively. Since all animals generate heat internally to some extent, energetics is closely linked to the problem of heat management and thermoregulation. For example, homeothermic or ‘warm-blooded’ animals (birds and mammals) must produce a great amount of heat in order to maintain a high and constant body temperature in cold as well as in warm surroundings (Schmidt-Nielsen, 1997). Moreover, natural environments can be extremely variable in their thermal attributes and consequently animals show behavioural and physiological adaptations that enable them to cope with these external gradients.

In recent years, there has been a tremendous increase in methodologies and techniques applicable to studies of energy expenditure and thermoregulation. This is particularly true for the study of daily energy requirements and body temperature rhythms of wild animals behaving normally in their natural habitats. In this contribution, I therefore review methods for the study of energetics and mechanisms of temperature regulation in primates (although these can generally be applied to almost all mammalian species). I also briefly mention other possibilities for physiological measurements. All procedures described here require capture of the study animals, and some require invasive surgical intervention. They therefore raise ethical questions when dealing with wild animals and/or endangered species, and require governmental permits and authorisation.