Food Prehension and Manipulation in Microcebus murinus (Prosimii, Cheirogaleidae)

Abstract

Among primates, apes and monkeys are known to use their hands and to exhibit independent control of their fingers. In comparison, Prosimii are thought to have less digital individualization and to use their mouth more commonly for prehension. Unfortunately, prehension and manipulation studies in Prosimii have been conducted in conditions constraining the subject to grasp with the hand. Moreover, the effect of food size remains unexplored, even though it could affect the use of the hands versus the mouth. Thus, whether prosimians use the hand or the mouth to grasp and manipulate food items of different sizes in unconstrained conditions remains unclear. To address this question, we characterized the eating and manipulation patterns of Microcebus murinus in unconstrained conditions, using three food sizes. The results showed that M. murinus showed (i) an eating pattern similar to that of rodents, with smaller food items being grasped with the mouth, (ii) a greater tendency to use the hands for prehension of larger foods, and (iii) plasticity during food manipulation similar to that which has been observed in rodents. These results are discussed in the framework of grasping in mammals and are used to discuss the origins of prehension in primates.

Substrate Diameter and Orientation in the Context of Food Type in the Gray Mouse Lemur, Microcebus murinus: Implications for the Origins of Grasping in Primates

“…The use of the mouth rather than hands to grasp static foods is consistent with previous studies of the grasping of small sized fruit items (Reghem et al 2011;Scheumann et al 2011;Ward and Hopkins 1993). Moreover the use of the mouth for the grasping of small static objects is commonly observed in lemuriforms (Peter 1962), other primates (strepsirrhines : Pollock 1977;Ward and Hopkins 1993;platyrrhines: Singer and Schwibbe 1998), and nonprimates such as rodents (Whishaw et al 1998), marsupials (Ivanco et al 1996), and tree shrews (Joly et al 2012).…”

“…One or both hands are typically used to catch fast moving foods, e.g., insects, particularly in platyrrhines, strepsirrhines, rats, opossums, and kinkajous (Charles-Dominique 1977;Ivanco et al 1996;Martin 1972a, b;McClearn 1992;Nekaris 2005;Niemitz 1984;Peter 1962). Yet, many of these species preferentially use the mouth to grasp static foods such as fruit (Pollock 1977;Reghem et al 2011;Rothe 1971;Scheumann et al 2011;Singer and Schwibbe 1998;Toussaint et al 2013;Whishaw et al 1998). However, the substrates used during food grasping are rarely considered and as such it remains largely unknown how these two parameters interact.…”

“…Gray mouse lemurs feed primarily on fruits and arthropods in the wild (Dammhahn and Kappeler 2008;Siemers et al 2007). Laboratory studies have shown that they preferentially use the mouth to grasp static food items such as fruits (Reghem et al 2011;Scheumann et al 2011;Toussaint et al 2013;Ward and Hopkins 1993). However, the use of the hands increases when grasping mobile prey such as insects (Toussaint et al 2013), a fact supported by observations in the wild (Charles-Dominique 1977;Martin 1972a, b;Siemers et al 2007).…”

Hands of early primates

“…A mesaxonic grip places the third digit on the midline while the first and second rays oppose the fourth and fifth. Less ulnar deviation is required as the axis of the grip is moved laterally from telaxonic to mesaxonic (Reghem et al, 2011).…”

Hand preference in fast-moving versus slow-moving actions in capuchin, Sapajus spp., and squirrel monkeys, Saimiri sciureus

“…In contrast, in many primates and rats, Rattus norvegicus, grasping stationary food induces a strong use of the nearest hand to the location of the food (Ivanco, Pellis, & Whishaw, 1996;Lehman, 1993;Meunier, Blois-Heulin, & Vauclair, 2011;Warren, 1980). The subject does not have to anticipate motion of a stationary item and the forelimb movement is more stereotypical than for grasping a moving target (Christel & Billard, 2002;Reghem, Tia, Bels, & Pouydebat, 2011). However, a group bias, but not a population bias, favouring the use of the right paw for reaching in rats has been reported (Güven, Elalmis, Binokay, & Tan, 2003).…”