Prey capture efficiency in brown capuchin monkeys (Cebus apella) is influenced by sex and corpus callosum morphology

Abstract

The diet of capuchin monkeys consists largely of fruits, but these monkeys commonly prey upon insects and other invertebrates as well as vertebrates such as lizards, birds, and fish. Capturing small fast-moving prey requires the ability to process complex visuospatial information such as motion detection, shape, and pursuit. Here we report the results of an experimental investigation into whether capuchins display sex differences in prey capture efficiency, and whether these differences are associated with the morphology of regions of the corpus callosum (CC) involved in visuospatial ability. We examined the prey capture behavior of seven capuchin subjects (four female, three male) in the laboratory by providing subjects opportunities to fish. Additionally, we obtained structural magnetic resonance images from these subjects to determine if spatial-ability was related to CC anatomy. Over 30 fishing trials, we recorded the number of prey capture attempts, success rate in capturing fish, and hand techniques used in these attempts. Males were significantly faster and more successful than females at capturing prey. In addition, males had smaller total CC:brain ratios than females. Males displayed a left hand bias, as well as significant unimanual usage, whereas females displayed no significant preference for hand usage. Individual capture times were correlated with total CC:brain ratio. Taken together, our results suggest a relationship between prey capture efficiency, sex, and the degree of brain lateralization.

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

“…Contrary to our findings of left-hand preference for four of five female capuchins in capturing crickets, a previous study in which tufted capuchin monkeys captured freely swimming small fish reported a significant left-hand preference for male capuchins (N ¼ 3) whereas females (N ¼ 4) showed no significant hand preference (Hellner-Burris et al, 2010). Sex may not be a parameter influencing the hand preference in capuchins.…”

“…This is suggested by the finding that mouse lemurs, Microcebus murinus, grab stationary food with the mouth but moving prey with the hands (Toussaint et al, 2013). In primates, catching fast-moving prey involves the integration of visuospatial information about the trajectory and speed of the prey with aimed rapid movement of the forelimb (Hellner-Burris et al, 2010). The right hemisphere is known to be used for spatial processing in many species (rats: Cowell, Waters, & Denenberg, 1997; chickens, Gallus gallus domesticus: Tommasi & Vallortigara, 2004;humans: Wendt & Risberg, 1994;De Renzi, 1982;other species: Vallortigara & Rogers, 2005).…”

Forelimb preferences in quadrupedal marsupials and their implications for laterality evolution in mammals

“…In placental mammals the size of the corpus callosum was found to be inversely linked with asymmetry expression [96-98]. Furthermore, the sexual dimorphism in the corpus callosum size seems to be associated with differences in motor laterality in males and females [99-102]. The alternative way of interhemispheric connection may result in a fundamentally distinct mechanism of sex effect on limb preferences in marsupials compared to placentals.…”

Age-related differences in corpus callosum area of capuchin monkeys

“…An example of how growth in the tracts of the CC might be associated with the development of skilled foraging concerns the complex foraging skill of prey capture. The increase in posterior region of the CC, the splenium, which connects information between parietal and temporal lobes and is associated with visuospatial skills, may be linked to skills such as prey capture (Hellner-Burris et al 2010), Phillips, unpublished results). Ongoing longitudinal research in our laboratory is exploring these questions, and has the potential to provide a more accurate means of tracking the development of the CC in capuchins and integrating brain development with development of cognitive and motor abilities.…”