In primates, the advantage of trichromacy (i.e., color vision expressed by most humans) over dichromacy (i.e., color vision expressed by many colorblind humans) has been linked to the detection of yellowish/reddish targets against a background of mature green leaves. Nevertheless, mostly because of studies conducted in humans, we know that achromatic cues might also play an important role in object identification, particularly when camouflage is involved. For instance, dichromacy favors the detection of camouflaged targets by exploitation of shape cues. The present study sought to evaluate the relative importance of color and shape cues on the detection of food targets by female and male marmosets (Callithrix jacchus). Animals were observed with respect to their foraging behavior and the number of food targets captured. We confirmed that females are advantageous in detecting conspicuous food against a green background and revealed that females and males rely on shape cues to segregate cryptic food. Unexpectedly, males outperformed females in cryptic food foraging, while camouflage improved males’ (but not females’) performance. Here we show that dichromats could potentially benefit from a better segregation of green natural targets (e.g., immature fruits, green insects, and gum trees) when viewed against a green dappled background.

在灵长类动物中，三色性（即大多数人表达的色觉）优于二色性（即许多色盲人表达的色觉）的优势与成熟绿叶背景下黄色/红色目标的检测有关。尽管如此，主要是因为在人类中进行的研究，我们知道消色差线索也可能在物体识别中发挥重要作用，尤其是在涉及伪装时。例如，二色性有利于通过利用形状线索来检测伪装目标。本研究旨在评估颜色和形状线索对雌性和雄性狨猴（Callithrix jacchus）。观察动物的觅食行为和捕获的食物目标数量。我们证实雌性有利于在绿色背景下检测显眼的食物，并揭示雌性和雄性依靠形状线索来分离神秘食物。出乎意料的是，雄性在神秘的食物觅食方面的表现优于雌性，而伪装提高了雄性（但不是雌性）的表现。在这里，我们表明，当在绿色斑驳的背景下观察时，二色视者可能会受益于更好地分离绿色自然目标（例如，未成熟的水果、绿色昆虫和胶树）。