The White-fronted Capuchin (Cebus albifrons) is a New World primate, endemic to six different countries in South America: Bolivia, Brazil, Colombia, Venezuela, Ecuador and Peru. The species is also divided into several different subspecies.
Just like any other capuchin monkey, it is also an omnivorous animal, feeding primarily on fruits, although it can also eat invertebrates and other plant parts. It is a polygamous animal and lives on fairly large groups (15 up to 35 individuals), reproductive females each giving birth to a single young at biennial intervals.
Defler and Hernández (2002) established a neotype from the population that was called Cebus albifrons albifrons by Hernández C. and Cooper (1976). Another problem has been that the taxon C. a. unicolor described by Spix (1823) and further defined by Hershkovitz (1949) was indistinguishable from C. a. albifrons; the two are synonymous (Hernández C. and Cooper, 1976; Defler and Hernández C., 2002). Hernández C. and Cooper (1976) describe eight subspecies for Colombia (including C. a. albifrons and C. a. unicolor), but it seems likely there are five, since C. a. versicolor includes C. a. pleei and C. a. leococephalus and C. a. unicolor is synonymous with C. a. albifrons. C. a. yuracus has been synonimyzed with C. a. cuscinus by Groves (2001).
Cebus a. unicolor (Spix, 1823) is also very light colored with yellowish tones and it seems clear that it is a synonym of C. a. albifrons (Defler and Hernández C., 2002).
Several years ago some specimens of Cebus were preserved from the Barranquilla market, which supposedly had come from the middle valley of the San Jorge River. It is difficult to determine whether these are C. capucinus or C. albifrons. Intermediate characteristics include a dark crown that is high and removed from the forehead. Also, the white parts in the face are more distinctively bald and the outside parts of the arms and legs are more clear; all of these characters suggest C. capucinus. The body is darker and more uniform than in individuals of C. a. malitosus. Also, some C. a. versicolor (pleei type) seen in the market at Magangué‚ and probably captured in the lower Cauca River, also show similar tendencies to the above, except that there are is no increase in the dark pigmentation. Based on these observations and on various "intermediate" specimens colored dark brown of C. capucinus from northern Colombia, it seems possible that an investigation of the contact zone between C. capucinus and C. albifrons ultimately could show that these forms are conspecific. Another critical zone for this analysis is an area in northeast Ecuador where C. a. ecuatoriales (Allen, 1914) and C. capucinus are found, although neither sympatric distributions or intergradation have as yet been determined (Hernández C. and Cooper, 1976).
Outside of Colombia, C. albifrons is found from the Andes throughout eastern Ecuador, Peru and northern Bolivia to the Tapajós river in Brazil, south of the Amazon River. North of the Amazon River the species is found in the southern parts of the Venezuelan Federal State of Amazonas and in northern Brazil between Colombia and the Branco River.
Cebus albifrons albifrons is very common in the eastern half of El Tuparro National Park. It is less common but still not too hard to find in Amacayacu National Park. Cebus a. yuracus is known south of the Putumayo River, but this author does not know a particularly good place to see it. Cebus a. versicolor is widespread on the middle-Magdalena River and is observable in preserved woodlots of protected fincas. Cebus a. malitiosus is easy to observe in Tayrona National Park, east of Santa Marta. Cebus a. cesarae can be located in the Serranía del Perijá east of Valledupar, Cesar, although the author has not observed this subspecies in its natural habitat.
This species has been studied in Colombia by Defler (1979a, 1979b, 1980, 1982, 1985a), in two different sites in Peru by Soini (1986a) and Terborgh (1983), and in Trinidad by Phillips (1998a, 1998b, 1999; Phillips and Newlon (2000, 2001), Phillips and Shauver (2001) and Phillips and Abercrombie (2003).
In eastern Vichada these monkeys are found in large groups of around 35 individuals, while to the south in closed forest (perhaps as a result of competition with C. apella) they have average group sizes of around 8-15 individuals. A group in Vichada used a home range of about 1.2 km² (Defler, 1979a), while Terborgh (1983) found a home range of more than 1.50 km². Near the type locality in gallery forest and islands of forest in Vichada, the species has an ecological density of around 30 individuals/km² (Defler, 1979a). In forests with closed-canopy in Colombia and in southern Vichada, many areas have very low densities. Around the lower Apaporis River, for example, densities are less than one individual/km² and the size of the groups is around 15 individuals. Low densities in many parts of the Colombian Amazon make it difficult to detect the presence of the species in many parts.
Terborgh (1983) found an average of 1,800 m for the day range of a group, and he calculated the following time budget of the study group in Manú National Park, Peru (18% rest, 21% travel, 22% feeding on plant material and 39% feeding on insects; total feeding 61%). These primates are primarily quadrupeds, although they utilize a great variety of gallops, jumps, falls and climbing. During certain times of the year C. albifrons is extremely terrestrial, especially when there is a scarcity of available fruits and the troop must search for arthropods in the dry leaves of the forest floor. In some parts of the Llanos Orientales where this species is found, these primates often walk over the grassy savanna between forests, leaving well-beaten trails. Cebus albifrons in Vichada use preferential trees for sleeping at heights of 25-30 m. The palm Attalea regia is often used for sleeping in this zone.
All species of Cebus tend to have a rather similar diet in broad terms; they are omnivores, eating fruits and small invertebrates, small vertebrates and birds' eggs, which they forage at all levels of the forest, frequently descending to the forest floor. In northern Colombia during the dry season when there are few fruits to be found, C. albifrons spends more than half their time on the ground, searching for and capturing small prey. These animals are extremely good at manipulating objects, and spend a great deal of time examining dry leaves from which they collect invertebrates (for example small beetles and ants' eggs) from rolled up leaves. These primates hunt frogs and drink the water which accumulates in the spaces between the bracteoles of the common plant Phenakospermum guianense, where the frogs hide. Hunting amphibians seems to be a cultural phenomenon which the members of each group learn. P. guianense is commonly present in large, dense stands in some types of forest.
In Manú National Park the animal material in the diet includes frogs, lizards, small mammals and birds' eggs as well as many invertebrates, including orthopterans, lepidopterans and hymenopterans (especially ants and wasp larvae). In the Pacaya–Samiria National Reservation, Soini (1983) saw these monkeys eating tent caterpillars. Terborgh (1983) identified 73 species of plants from 33 families consumed by this primate. The Moraceae was the most important family by a wide margin, counting the number of species (17) eaten, equivalent to 23.3% of all plant species consumed. Importance values for plant families consumed by Cebus albifrons in one study are as follow (Terborgh, 1983): Moraceae (17, 23.3%); Leguminosae (5, 6.8%); Araceae (4, 5.5%); Bombacaceae (4, 5.5%); Palmae (4, 5.5%).
Defler (1979a) collected 40 species of plants from 23 families eaten by this primate in Vichada con los siguientes valores de importancia according to species consumed per family: Arecaceae (7); Moraceae (6); Chrysobalanaceae (3); Leguminosae (3); Passifloraceae (2); Bromeliaceae (2); Burseraceae (2); Bombacaceae (1); Celastraceae (1); Connaraceae (1); Euphorbiaceae (1); Lecythidaceae (1); Maranthaceae (1); Melastomataceae (1); Anacardiaceae (1); Myrtaceae (1); Anonaceae (1); Musaceae (1); Apocynaceae (1); Orchidaceae (1); Araceae (1); Rubiaceae (1); Bignoriaceae (1).
In terms of importance value, palms are highly valued by all species of Cebus. In El Tuparro National Park in Colombia, the lovely and rather common palm Maximiliana regiae was a key species for this primate, the nuts being a principal food (Defler, 1979a). In Manú National Park in Peru the palms Astrocaryum and Scheelea were the most important palm genera, but perhaps not at the same level as Maximiliana in El Tuparro. Also, at Manú various species of Ficus were very important to C. albifrons; this emphasis on Ficus was not observed in the El Tuparro study, although this study did not include an entire year. Nevertheless, research on other species suggests the importance of palms as "key species" and the lack of importance of Ficus in such habitats as gallery forests in the llanos of Colombia and Venezuela, contrasting with their high importance in more fertile habitats like Manú.
Cebus albifrons takes advantage of almost any water source, drinking water from tree holes when available, but also drinking from brooks and springs when necessary. During the driest season in Vichada the group studied by Defler (1979a, 1979b) went to the ground every day to a water seep from under a huge boulder, which was the only water source available in their home range.
This species of Cebus is polygamous. The male mounts the female, holding her legs with his hind feet, and copulates with her for a few minutes. Although the time of gestation is unknown, it is probably around 160 days like C. apella. Usually one infant is born. Observations of a newborn in El Tuparro National Park showed the process by which the newborn discovered the appropriate position for riding on the mother. Newborns ride oriented sideways over the mothers' shoulders, but during the first days the baby holds on to any part of the mother such as the base of the tail, the tail, the legs, and the arms before discovering and learning that the position over the shoulders is best and most secure. After several weeks the baby makes the change from the sideways position over the shoulders to riding on her back.
All the members of the troop are interested in the newborn, and they take advantage of any opportunity to examine and look at its genitals if the mother permits it. With time the baby begins to climb up on other members of the troop, including the adult males who are interested in protecting the little one. Playing behavior is principally with a companion, and all members of the troop from the alpha male, the mother and all young members of the group solicit play with the young one.
Adult males are notably tolerant of each other in the group, but they are very aggressive towards males of other groups. Defler (1979b) described some intergroup aggressive behaviors in El Tuparro, which resulted in one group fleeing towards the central parts of their territory. Alpha males seem to exercise a "control position" at the center of the group, since all members are extremely conscious and alert to his location, and they all observe his reactions. If the alpha reacts with intense fear or panic or if he pays close attention to something, all members of the troop react similarly. The presence of adult males seems to lend psychological support to the smaller adult females. Defler (1979b) noticed that more timid females often became quite aggressive towards him when a male appeared on the scene, although the females often needed to press up against the flank of the male for reassurance.
Vocalizations are variable, and some are listed as follow (Defler, 1979b): (1) ua - a soft bark given repeatedly and used by all members of the group when danger is perceived; (2) ya - excited animals around the alpha, towards alpha and towards perceived danger; (3) eh-eh - threat towards potential danger, but especially adult females; accompanied with open mouth showing teeth (OMT); (4) squeaky hinge - threat given especially by young animals; (5) squeal - conflict within the group during a fight; (6) whistle - conflict in the group of a young animal; (7) ahr - a lost animal; others answer this call, apparently to direct it back to the group; (8) uh!uh!uh! - a common vocalization during feeding which may allow contact to be maintained and show general contment; (9) uch!uch! - an animal trying to keep up with the group; (10) warble - young animals establishing contact or coming close to an adult; (11) purr - close and pacific contact; (12) chirriar -pacific interaction of young ones during play.
Perhaps the most important display is the behavior of breaking branches, which all members of the group. Even infants break small branches (or twigs), letting them fall to the soil, but the most spectacular is the alpha male who chooses large, dry branches which he hits with his hands and feet in spectacular jumps, so that they fall. Usually such branches make a tremendous sound as they fall through the other branches, and the members of the group become very excited and chatter loudly. This behavior is quite commonly discharged towards an observer when the animals have lost their fear.
These primates frequently travel with Saimiri sciureus and at other times with Cebus apella and Alouatta seniculus. The small hawk Harpagus bidentatus often accompanies these monkeys, exactly as it does other species of primates. Cebus albifrons feels threatened by avian predators, and they are very vigilant around any large bird of prey. In Vichada, Defler (1979, 1980) observed Eira barbara, Boa constrictor and the raptor Spizaetus ornatus trying to capture the monkeys, and these primates always were cautious around large birds. After detecting the Eira barbara and Boa constrictor the members of the troop showed little fear and caution, even though these animals had been trying to capture the monkeys. The most common behavior after detecting a potential ground predator is "ya-ya" vocalization and branch breaking over the head of the potential predator, similar to the display of the primate Lagothrix lagothricha. In contrast, after being frightened by a male Spizaetus ornatus the monkeys screamed intensely only once, then hid quietly, some descending to the ground to sneak away.