Rev. Biol. Trop., 35(2): 287-297, 1987. Troop movement and food habits of white-faced monkeys in a tropical-dry foresto Daniel Moscow* Associated Colleges of the Midwest, Apartado 1026 5, San José, Costa Rica. Christoper Vaughan Posgrado en Manejo de Vida Silvestre, Universidad Nacional, Heredia. (Received December 12, 1986) Abstract: Home-range, movement and activity patterns and diet of a group of 16 white-faced monkeys (Cebus capucinus) were studied in a Costa Rican tropical dry forest at the end of the dry season (March and April) cf 1982. The troop used an area of .6 7 km2 and moved an average of 4.5 km ± 0.6 daily. Three basic daily activities were identified: resting, moving and feeding. Resting was greatest between 1000-1500 hours. Movement, which was strongly correlated with feeding, occurred most between 0500-0900 hrs and 1300-1800 hrs. The primates were omnivores, feeding on parts of 27 species of plants, four species of insects and an Anolis lizard. The white-faced monkey or capuchin, Cebus of Nicoya, Guanacaste Province, Costa Rica. capucinus imitatar Thomas (Primates: Cebi­ The refuge is found at 10030' N and 85030' W. dae), is found in a wide variety of forest types Palo Verde is about 7,542 ha in size and situat­ from Belize to Panama (Hall 1981). This ed in the tropical-dry forest life zone (Tosi monkey is omnivorous and feeds mainly on 1969). Within the refuge, nine vegetation types fruits and seeds but also on flowers, woody tis­ were described: mangrove swamp, seasonal sue, young shoots, insects, and small vertebrates marsh, fresh-water flooded forest, lowland de­ (Defler 1979, Freese 1976, Freese and ciduous forest, deciduous forest on limestone Oppenheimer 1981, Hladik et al. 1971, Oppen­ hills, evergreen forest, overgrown pasture, Aca· heimer 1960). However, troop movement has cia scrubland and pasture (Vaughan et al. received little attention. The objectives of this 1982). study were to describe dai1y activity patterns Annual rainfall at nearby Puerto Humo for and food habits of a C. capucinus troop in a the 1961 to 1970 period averaged 2296 mm, tropical-dry forest during the latter part of the 91% of which fell between May and October. dry season. Mean annual temperatures of 370C are com­ mono Elevation varies from 1 2 to 232m. The late-dry season months of March and April have STUDY AREA AND STUDY TROOP little rain, relatively abundant fruit production, and extreme temperature differences between The Dr. Rafael Lucas Rodriguez Caballero areas of different vegetation types. National Wildlife Refuge (hereafter referred to The study area was about 100 ha in size and by its popular name, Palo Verde) is located on located on the southern shope of Cerro Guaya­ the northern bank of the Tempisque River, 20 cán, one of two prominent limestone hills with­ kilometers from the river's outlet into the Gulf in the wildlife refuge. Three forest types were described in this study area. These included: deciduous, semi-deciduous and evergreen, defi­ (*) Present Address: Department of Plant Pathology, University of California, Berkeley, California. ned as individual trees retaining respectively, 287 288 REVISTA DE BIOLOGIA TROPICAL 0-25%, 25-75% and greater than 75% of their large-scale directional travel was considered, leaves during the latter part of the dry season. while small-scale movements were exc1uded The study troop consisted of three old and two from the map. Daily distance traveled by the young adult males, three adult fe males, seven troop was calculated by summing all measured juveniles and one infant for a total of 16 indivi­ distances between consecutive estimated troop duals. positions. Home range was estimated by using METHODS the minimum convex polygon of all troop posi­ tons calculated (Mohr 1947). The study was conducted from 6 to 25 Statistical notation fo llowed that of Sokal March and from 13 to 29 April 1982. Our ob­ and Rolhf (1981). servations began about 15 min before sunrise (05 15 hrs) when capuchins were leaving their RESULTS AND DISCUSSION sleeping sites. The troop was followed until about 20 min after sunset (1800 hrs) when it F or each hour of the day, between 220 and = = settled into trees to sleep. A group of more 360 min (x 314.4 min; S.D. 45 .2) of obser­ than six monkeys was arbitrarily defmed as a vatio n time was collected. The ratio of observa­ troop and a group of six or less, as a sub-group. tions collected for adults and juveniles was The focal animal technique (Altmann 1974) 60:40, respectiveIy. This approxirnated the age was used for collecting activity data, where a class composition of 50: 50 of adults to juveni­ single capuchin was initially chosen at random les for the study troop. and fo llowed. Duration of each activity was re­ corded to the nearest minute which was the Troop home range. During March and April, 2 smallest time unit . Activity was grouped into the troop had ahorne range of 0.67 km . A hourIy periods and for one statistical test, into significantly greater proportion of diurnal activ­ two periods of fo ur and one of five hours. ity occurred in the evergreen fo rest compared When the fo cal animal separated from the troop to its total area in the study area (x2 = 8.4, dJ. or was lost by us, our observations was directed = 1, P<O .005). The evergreen forest occupied to the next capuchin seen. It was at times im­ only 5% of the home range , but the troop spent possible to pursue monkeys close enough to 32% of the daytime there (Table 1). In addi­ observe feeding activities. tion, 75% (12 of 16) of nights, about 50% of Four activities were studied: moving, resting, diurnal resting and a large proportion of fe eding drinkingand feeding. Movement was defmed as time, were spent in the evergreen foresto Sleep­ travel. Resting was described as a variety of re­ ing and resting sites occurred mostly in leafy latively stationary activities, including reclining mango (Mangifera indica) and oj oche (Brosi­ with or without closed eyes, sitting alert , mum alicastrum) trees fo und in evergreen and grooming, and play. Drinking involved ingestion semi-deciduous areas (Fig. 1). of water from waterholes. Feeding occurred On a daily basis, the troop occupied about when the focal animal searched fo r, picked, bit 30-50% of their overall home range area; similar or chewed a fo od source. The food unit was the to what Baldwin and Baldwin (1977) described plant part picked, bitten, or collected and par­ for the same species in Panama. In Palo Verde, tially or completely ingested. When the plant there are seven evergreen fo rest patches, and part was a fruit, the fruit part consumed was waterholes are fo und in each. We observed daily also annoted. For example, the Spondias purpu­ visits to water sources by capuchin troops. The rea tree was a food source and the fleshy meso · evergreen fo rest is an invaluable so urce of fo od, carp , the food unit. Each minute of feeding time water and cover during the dry season for capu­ usually included ingestion of one or more chins and other wildlife species. fo od units. Food units and the relative amounts of food discarded or dropped were determined Troop movement. Troop movement was re­ by direct observation of feeding capuchins and corded for six days from 0500-1800 hrs. Daily when possible quantitative examination of fresh travel was 3.9, 4.0, 4.2, 4.5 , 5.1 and 5.2 km (x food remains beneath fo od sources. = 4.5km; S.D. = 0.6). The capuchin troop sorne­ Troop position and time of day were recor­ times repeated a certain route fo ur times a day ded on a map when abrupt changes occurred in (Fig. 2 and 3). They also crisscrossed estab­ capuchin direction of travel. Only relatively lished routes and even backtracked. Sorne MOSCOW & VA UGHAN: W ite-faced monkeys in a tropical dry forest 289 TABLE 1 Diurnal use of fo rest types by a white·fa ced monkey (Cebus capucinus) troop. Palo Verde. (March·April, 1982) Forest Type Home Range Time Spent in Forest Type ha % hrs % Evergreen 3.3 ( 5) 19.9 (32) Semideciduous 6.0 ( 9) 9.3 (15) Deciduous 22.1 (33) 15.5 (25) Deciduous with evergreen pitches 35.6 (53) 17.4 (24) Total 67.0 (lOO) 62.1 (lOO) routes were highly defined, and capuchins On many occasions, especia11y in deciduous moved through specific trees. Others were gen· f o rests, several adult capuchins walked at eralized, and the monkeys trayeled in particular ground level while the remainder of the troop directions via many nearby paths. continued arborea11y. These terrestrial move­ Troop movements of C. capucinus were ments covered up to 50 m, lasted up to six min observed by Baldwin and Baldwin (1977) on and inc1uded foraging. Baldwin and Baldwin the Burica Peninsula in Panama, with daily path (1977) reported that C. capucinus foraged for lengths ranging from 0.6 to 1.5 km. Clutton­ insects for distances of more than 20 meters Brock and Harvey (1977) have listed sornedaily along the ground. Moreover, Defler (1979) path lengths for 56 primate species belonging to observed that C. albifrons spent up to 50% of eight families. Our value of 4.5 km.for C. capu­ their active period foraging at ground level dur­ cinus exceeded the daily path lengths of all 56 ing the dry season (February) in Colombia. species with the exception of three species of Pap io.