Raw data on hand usage for the macaques in the unimanual and the bimanual food-reaching tasks (n = 16), and the hand-performance-differentiation task (n = 10).

<p>Raw data on hand usage for the macaques in the unimanual and the bimanual food-reaching tasks (n = 16), and the hand-performance-differentiation task (n = 10).</p

Apparatuses for the unimanual food-reaching task (a), the bimanual food-reaching task (b), and the hand-performance-differentiation task (c).

<p>Reproduced, with permission from Wiley Periodicals, Inc., from Mangalam et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0119337#pone.0119337.ref023" target="_blank">23</a>] © 2013 Wiley Periodicals, Inc.</p

Hand and Cheek Pouch Usage by the Macaques (n = 14).

<p>‘L’ and ‘R’ indicate left and right respectively;</p>a<p>preferred hand/cheek pouch: z≤1.96: L; −1.96</p

Relationship between (a) the latency in food extraction using the preferred hand (i.e., the maneuvering hand, see mangalam et al. [1]) and the laterality in hand performance (LHP) in the hand-performance-differentiation task, and (b) the LHP in the hand-performance-differentiation task and the absolute difference between the laterality in hand usage in the unimanual and the bimanual food-reaching tasks. n = 10.

<p>Relationship between (a) the latency in food extraction using the preferred hand (i.e., the maneuvering hand, see mangalam et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0119337#pone.0119337.ref001" target="_blank">1</a>]) and the laterality in hand performance (LHP) in the hand-performance-differentiation task, and (b) the LHP in the hand-performance-differentiation task and the absolute difference between the laterality in hand usage in the unimanual and the bimanual food-reaching tasks. n = 10.</p

Relationship between Hand and Cheek Pouch Usage among the Macaques (n = 14): while Filling (A) and Emptying (B).

<p>Relationship between Hand and Cheek Pouch Usage among the Macaques (n = 14): while Filling (A) and Emptying (B).</p

Mean ± se HI values per reaching-for-food task for the red howler monkeys (scattered: n = 12; inside a suspended container: n = 9) and the yellow-breasted capuchin monkeys (scattered: n = 6; on the opposite side of a wire mesh, inside a suspended container, inside a portable container: n = 7). Vertical bars indicate SE.

<p>Mean ± se HI values per reaching-for-food task for the red howler monkeys (scattered: n  =  12; inside a suspended container: n  =  9) and the yellow-breasted capuchin monkeys (scattered: n  =  6; on the opposite side of a wire mesh, inside a suspended container, inside a portable container: n  =  7). Vertical bars indicate SE.</p

Hand Usage across the Different Reaching-for-Food Activities for the Red Howler Monkeys and the Yellow-Breasted Capuchin Monkeys.

<p>‘R’ and ‘L’ indicate the frequency of usage of the left and right hand respectively.</p><p>Hand Usage across the Different Reaching-for-Food Activities for the Red Howler Monkeys and the Yellow-Breasted Capuchin Monkeys.</p

The overall mean ± se HI values for the red howler monkeys (n = 12) and the yellow-breasted capuchin monkeys (n = 7). *p <0.050.

<p>The overall mean ± se HI values for the red howler monkeys (n  =  12) and the yellow-breasted capuchin monkeys (n  =  7). *p <0.050.</p

Mean ± se HI values per body posture for the red howler monkeys (sitting: n = 9; tripedal, hanging: n = 11) and the yellow-breasted capuchin monkeys (sitting and tripedal: n = 7; bipedal, clinging, hanging: n = 6). Vertical bars indicate SE.

<p>Mean ± se HI values per body posture for the red howler monkeys (sitting: n  =  9; tripedal, hanging: n  =  11) and the yellow-breasted capuchin monkeys (sitting and tripedal: n  =  7; bipedal, clinging, hanging: n  =  6). Vertical bars indicate SE.</p

Hand Usage According to the Different Body Postures Acquired by the Red Howler monkeys and the Yellow-Breasted Capuchin monkeys.

<p>‘R’ and ‘L’ indicate the frequency of usage of the left and right hand respectively.</p><p>Hand Usage According to the Different Body Postures Acquired by the Red Howler monkeys and the Yellow-Breasted Capuchin monkeys.</p