Energetic costs of feeding in 12 species of small-bodied primates

Abstract

There are no comparative, empirical studies of the energetic costs of feeding in mammals. As a result, we lack physiological data to better understand the selection pressures on the mammalian feeding apparatus and the influence of variables such as food geometric and material properties. This study investigates interspecific scaling of the net energetic costs of feeding in relation to body size, jaw-adductor muscle mass and food properties in a sample of 12 non-human primate species ranging in size from 0.08 to 4.2 kg. Net energetic costs during feeding were measured by indirect calorimetry for a variety of pre-cut and whole raw foods varying in geometric and material properties. Net feeding costs were determined in two ways: by subtracting either the initial metabolic rate prior to feeding or subtracting the postprandial metabolic rate. Interspecific scaling relationships were evaluated using pGLS and OLS regression. Net feeding costs scale negatively relative to both body mass and jaw-adductor mass. Large animals incur relatively lower feeding costs indicating that small and large animals experience and solve mechanical challenges in relation to energetics in different ways. This article is part of the theme issue ‘Food processing and nutritional assimilation in animals’.

Introduction: food processing and nutritional assimilation in animals

“…Energy costs provide an important performance metric for the locomotor system, but the role of energy costs in feeding system morphology and adaptations is debated and largely untested [13,59,60]. Wall et al [61] actually measured the energetic costs of feeding in a wide range of primates, and their data provide a fundamental baseline for testing hypotheses about the importance of energetic efficiency in driving the evolution of intraoral feeding behaviours in mammals, in addition to evidence previously presented for feeding in select animals [62][63][64]. While straightforward, measures of feeding performance have only been obtained from select vertebrates and invertebrates, leaving outstanding questions about how these measures relate to each other and vary in correspondence with changes in morphology, ecology and behaviour.…”

“…However, studies relating food material properties to oral processing in vertebrates are limited outside of primates (but see, [44,77,81]). In this special issue, Stilson et al [21], Laird et al [32], Wall et al [61] and Panagiotopoulou et al [56] all explore effects of varying food substrates during oral processing. Despite the importance of understanding the physics of a food substrate, this element of oral processing has thus far had a relatively limited effect on linking diet and morphology within primates [14].…”

“…[ 32 ], Wall et al . [ 61 ] and Panagiotopoulou et al . [ 56 ] all explore effects of varying food substrates during oral processing.…”