Reynoso-Cruz José Eduardo, Rangel-Negrín Ariadna, Coyohua-Fuentes Alejandro, Canales-Espinosa Domingo, Dias Pedro Américo D
Laboratorio de Ecología del Comportamiento de Primates, Instituto de Neuroetología, Universidad Veracruzana, Av. Dr. Luis Castelazo Ayala S/N, Colonia Industrial Animas, 91190, Xalapa, Veracruz, Mexico.
Laboratorio de Adaptación Animal, Facultad de Psicología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.
Primates. 2016 Apr;57(2):161-6. doi: 10.1007/s10329-016-0513-7. Epub 2016 Jan 22.
Food intake (i.e., the amount of food consumed by an individual) is a crucial measure for studying feeding behavior, but its measurement requires high visibility of individuals and long recording sessions, which are often difficult to accomplish under field conditions. As a consequence, studies on the feeding behavior of primates typically do not estimate food intake directly, and focus rather on studying dietary patterns through indirect measures of food intake, such as time spent feeding, number of food bites and food intake rates. The aim of the present study was to determine the validity of these estimators of food intake in mantled howling monkeys (Alouatta palliata) by comparing the estimations with the direct measurement of food intake. We recorded 97 feeding episodes of two male and two female adults, during which we determined the number of ingested food units (i.e., number of leaves and number of fruits), the number of bites taken and time spent feeding. After weighing units of food similar to those consumed, we calculated food intake and mean intake rates per food type (ripe fruits, unripe fruits, mature leaves, and young leaves). The number of bites taken by mantled howling monkeys during feeding episodes was strongly related to food intake, and this relationship was not affected by the type of food ingested. In contrast, neither time spent feeding nor food ingestion rate were related to food intake. These results suggest that the number of bites could be used as a valid proxy to study food intake in this species, whereas the other two measures are likely to yield inaccurate estimates of food intake.
食物摄入量（即个体消耗的食物量）是研究进食行为的一项关键指标，但其测量需要个体具有较高的可见度以及较长的记录时段，而这在野外条件下往往很难实现。因此，对灵长类动物进食行为的研究通常并不直接估算食物摄入量，而是侧重于通过食物摄入量的间接测量方法来研究饮食模式，如进食时间、咬食次数和食物摄入率。本研究的目的是通过将这些食物摄入量估算值与食物摄入量的直接测量值进行比较，来确定这些估算值在鬃毛吼猴（Alouatta palliata）中的有效性。我们记录了两只成年雄性和两只成年雌性的97次进食过程，在此期间我们确定了摄入的食物单位数量（即树叶数量和果实数量）、咬食次数和进食时间。在对与所消耗食物类似的食物单位进行称重后，我们计算了每种食物类型（成熟果实、未成熟果实、成熟树叶和嫩叶）的食物摄入量和平均摄入率。鬃毛吼猴在进食过程中的咬食次数与食物摄入量密切相关，且这种关系不受所摄入食物类型的影响。相比之下，进食时间和食物摄入速率均与食物摄入量无关。这些结果表明，咬食次数可作为研究该物种食物摄入量的有效替代指标，而其他两项指标可能会得出不准确的食物摄入量估算值。
