Effect of binocular visual cue availability on fruit and insect grasping performance in two cheirogaleids: Implications for primate origins hypotheses

Kemp, Addison D.

doi:10.1016/j.jhevol.2023.103456

Cited by 1 publication

(1 citation statement)

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“…The results of this experiment indicate that increased availability of binocular visual cues significantly improves leaping performance in a nocturnal small-bodied generalized arboreal quadrupedal taxon with facultative leaping. While similar experiments in C. medius and Microcebus murinus found that increased binocular cue availability provides a more substantial improvement in insect predation success (performance improvements >23%, Kemp, 2024 ), suggesting that the demands of capturing mobile prey were likely the primary driver of the evolution of primates' forward-facing eyes, this study presents a functional mechanism by which selection for improved grasp-leaping could also have contributed to selection for forward-facing eyes in the earliest crown primates.…”

Section: Discussionmentioning

confidence: 52%

Effects of binocular cue availability on leaping performance in Cheirogaleus medius: implications for primate origins

Kemp

2024

Journal of Experimental Biology

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Multiple competing hypotheses attribute the evolution of the suite of traits that distinguish primates from their closest relatives, including forward-facing eyes which create a wide field of binocular vision, to specific behavioral and ecological factors. The Grasp-Leaping Hypothesis suggests that the evolution of these traits in basal primates was driven by the demands of a form of leaping locomotion unique to primates. Whether the Grasp-Leaping Hypothesis provides a viable mechanism for the evolution of primates’ forward-facing eyes remains untested. To determine whether grasp-leaping locomotion may have contributed to driving the evolution of primates’ forward-facing eyes, the importance of vision within the binocular field for this type of leaping was evaluated experimentally in Cheirogaleus medius, one of the cheirogaleid primate species considered reasonable living analogues of the earliest primates. Availability of binocular visual cues was experimentally restricted using a head-mounted blinder that narrowed binocular visual field without altering the total visual field. Animals altered their launch behavior, reduced their horizontal leap speed, and were significantly more likely to select paths that offered the shortest available leaps when their binocular field was restricted. Restriction of binocular cue availability also significantly increased the probability of adverse landings even when statistically controlling for potentially confounding variables such as leap distance, horizontal leap speed, learning effects, etc. These results suggest a functional mechanism by which selection for improved grasp-leaping could also have contributed to the evolution of forward-facing eyes in the earliest crown primates.

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Section: Discussionmentioning

confidence: 52%