Saguinus Fuscicollis Research Articles

Use of Social and Ecological Information in Tamarin Foraging Decisions

A major consequence of group living is that foragers may rely on social information in addition to ecological information to locate feeding sites. Although conspecifics can provide cues as to the spatial location of food patches, individual foraging decisions also must include some assessment of the likelihood of obtaining access to a resource other group members seek. This likelihood differs in the 2 models generally proposed to explain intragroup social foraging: the information-sharing model and the producer-scrounger model. We conducted an experimental field study on wild groups of emperor (Saguinus imperator) and saddleback (S. fuscicollis) tamarins to determine the foraging strategies adopted by individual group members and their relationship to social rank, food intake, and the ability to use ecological and social information in making intra-patch foraging decisions. Individual tamarins applied different behavioral strategies compatible with a finder-joiner paradigm to solve foraging problems. About half of the individuals in each study group initiated 74%–90% of all food searches and acted as finders. Most alpha individuals adopted a joiner strategy by monitoring the activities of others' to obtain a reward. The individual arriving first at a reward platform enjoyed a finder's advantage. Despite differences in search effort, both finders and joiners presented similar abilities in learning to associate ecological cues with the presence of food rewards at our experimental feeding stations. We conclude that within a group foraging context, tamarins integrate social and ecological information in decision-making.

Factors Affecting Group Spread within Wild Mixed-Species Troops of Saddleback and Mustached Tamarins

We examined group spread and interindividual spacing within wild mixed-species troops of saddleback (Saguinus fuscicollis) and mustached (Saguinus mystax) tamarins. Mustached tamarin groups were spread over larger areas than those of saddleback tamarins. Group size and behavior affected group spread and interspecific proximity: larger groups of both species were dispersed over greater areas, and the larger troop had the lowest degree of interspecific proximity. Behavior also affected group spread and interspecific proximity: when traveling individuals were spread over a larger area, and the distance between heterospecifics was greater than when stationary. We examined spatial proximity using data on the distance from nearest neighbor. Overall, distance to nearest neighbor was not affected by group size. Based on specific behaviors, foraging saddleback tamarins were significantly nearer conspecifics than to mustached tamarins. Tamarins have polymorphic color vision, and trichromats—having 3 types of visual pigment—versus dichromatic individuals—with two types of pigment—may be better at perceiving yellow or russet colored predators and conspecifics than their dichromatic counterparts are. Color vision status affected spatial positioning, with vigilant trichromats being further from their neighbors than their dichromatic conspecifics were. We discuss the findings with respect to the ecology of the species. Specifically, interspecific differences in group spread and spatial proximity are related to differences in the supports used, and the effect of troop size on interspecific proximity is related to increased resource competition. The finding that trichromats are further from their neighbors represents the first example of a behavioral correlate of color vision ability in a wild species with polymorphic color vision, and is explained through the perception of predation risk.

The win-stay rule in foraging decisions by free-ranging titi monkeys (Callicebus cupreus cupreus) and tamarins (Saguinus imperator imperator and Saguinus fuscicollis weddelli).

Rainforest primates need to apply distinct foraging rules for efficiently using the spatial knowledge of the distribution of resources showing different temporal patterns of renewal. A win-stay rule is very important for exploiting abundant, long-lasting resources. Here, the author tests the use of this rule in wild groups of emperor tamarins (Saguinus imperator imperator), saddle-back tamarins (Saguinus fuscicollis weddelli), and titi monkeys (Callicebus cupreus cupreus) during a series of foraging tasks. Four feeding stations composed of 8 visually similar feeding platforms (2 containing a food reward and 6 containing a sham reward) were constructed. The location of food rewards was reliable during some experiments and unreliable during others. All 3 species consistently adopted a win-stay rule for returning to reward platforms when their location was predictable over time but stopped using it when their spatial distribution changed randomly across experimental trials.

Survey of the gastrointestinal parasites of the primate community at Tambopata National Reserve, Peru

AbstractThe main objective of this project was to provide baseline data on faecal parasites of groups of non‐human primates from Tambopata Research Center, Tambopata National Reserve, Peru. All primate species found in this area were sampled: red howler monkeys Alouatta seniculus, night monkeys Aotus vociferans, spider monkeys Ateles bezlebuth chamek, brown titi monkeys Callicebus brunneus, white‐fronted capuchins Cebus albifrons, brown capuchins Cebus apella, saddleback tamarins Saguinus fuscicollis and squirrel monkeys Saimiri sciureus. Individuals from four howler monkey troops, three brown titi monkey troops, two squirrel monkey troops and one troop each of night monkeys, spider monkeys, brown capuchins, white‐fronted capuchins and saddleback tamarins were sampled. Faecal samples were collected from July to October 2002 from 86 individuals. A concentration test was used to analyse faecal samples. Results indicate the presence of various protozoans, Ancyclostoma sp., Ascaris sp., Strongyloides stercoralis, Trichuris trichiura, Prosthenorchis elegans and Schistosoma mansoni.

Factors affecting vigilance within wild mixed-species troops of saddleback ( Saguinus fuscicollis ) and moustached tamarins ( S. mystax )

We examine vigilance within a mixed-species troop of saddleback (Saguinus fuscicollis) and moustached (S. mystax) tamarins over a complete year. Saddleback tamarins were consistently more vigilant than moustached tamarins. This may be linked to their preference for lower strata. In accordance with previous studies of other primates, vigilant tamarins of both species were significantly further away from their nearest neighbours, and were also at lower heights in the forest than non-vigilant individuals. There was no observed sex difference in the amount of time spent vigilant. In terms of modes of scanning, the saddleback tamarins looked up significantly more frequently than the moustached tamarins, whereas there was no difference between the species in the frequency of side sweeps. There were no differences between the sexes in the frequencies of either type of vigilant behaviour. The proportion of time spent vigilant was higher than average immediately prior to entering a sleeping site for saddleback tamarins, but not for moustached tamarins. Both species were more vigilant immediately after exiting a sleeping site than at other times of the day. There was significant variation in the amount of time devoted to vigilance over the course of the year. These findings are discussed with respect to the social structure, ecology and main predator threats facing these species.

Do female tamarins use visual cues to detect fruit rewards more successfully than do males?

Primates are unique among eutherian mammals for possessing trichromatic colour vision. It is generally proposed that trichromacy evolved to aid detection of ripe fruits against mature foliage. However, while trichromacy is routine in all Old World monkeys and apes (the catarrhines), a cone opsin polymorphism in New World monkeys (the platyrrhines) results in foraging groups with mixed capacities for chromatic distinction. Although 50–66% of female platyrrhines are trichromatic, all males are dichromatic. Here, we test the hypothesis that trichromatic platyrrhines use visual cues to detect fruit rewards more successfully than do males. Specifically, we ask whether female emperor tamarins, Saguinus imperator imperator, and saddleback tamarins, S.fuscicollis weddelli, are the first members of their foraging group to locate food patches; and, furthermore, whether they are more successful than males in using colour, shape and size cues to discriminate between sham and reward feeding sites. Our results show that females and males do not differ in their ability to locate or discriminate between feeding sites. We conclude that trichromatic vision in female tamarins does not confer an advantage for detecting yellow fruit rewards against mature foliage. Copyright 2003 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Experimental field study of the relative costs and benefits to wild tamarins (Saguinus imperator and S. fuscicollis) of exploiting contestable food patches as single- and mixed-species troops.

Several species of tamarins form stable mixed-species troops in which groups of each species feed, forage, rest, and travel together during much of the year. Although the precise set of factors that facilitate this ecological relationship remains unclear, predator detection and foraging benefits are presumed to play a critical role in maintaining troop stability. In this work we present data from an experimental field study designed to examine how factors such as social dominance and within-patch foraging decisions affect the costs and benefits to tamarins of visiting feeding sites as single- and mixed-species troops. Our data indicate that when they exploited contestable food patches (sets of eight feeding platforms, two of which contained a 100-g banana), each tamarin species experienced foraging costs when they arrived as part of a mixed-species troop. These costs were found to be less severe for emperor tamarins because they were socially dominant to saddle-back tamarins and could displace them at feeding sites. We conclude that the foraging benefits to tamarins residing in mixed-species troops are asymmetrical, and that at feeding sites in which the amount of food in a patch is insufficient to satiate all troop members, even minor differences in the timing of return to food patches and changes in troop cohesion have a measurable effect on the costs and benefits to participating tamarin species.

A comparative study on the cortico-hypoglossal connections in primates, using biotin dextranamine

The anterograde projections of the motorcortical tongue area to the hypoglossal nucleus and neighbouring structures were studied in the rhesus monkey, squirrel monkey, saddle-back tamarin and tree shrew. Biotin dextranamine served as tracer. Direct projections into the hypoglossal nucleus were only found in the rhesus monkey and squirrel monkey. All four species, however, showed a direct projection into the dorsal and parvocellular reticular formation which in turn projects into the hypoglossal nucleus. The findings suggest a phylogenetic trend in the projections of the motorcortical tongue area from non-primate mammals via non-human primates to man in the sense that the cortico-motoneuronal connection is strengthened towards man. This might be one reason for the superior role the tongue plays in human vocal behaviour in contrast to non-human vocalization.

Interspecific communication in mixed-species groups of tamarins: evidence from playback experiments

Long-call vocalizations have been hypothesized to serve as communicative signals both within and between tamarin species. Prior evidence for the use of long calls as interspecific signals, however, is based solely on observations of apparent countercalling between species. I conducted playback experiments with groups of wild saddle-back tamarins, Saguinus fuscicollis, and emperor tamarins, S. imperator, to test the hypothesis that long calls function as interspecific signals between tamarin species forming polyspecific associations. Results show that in the absence of any other external cues, lone groups of saddle-back tamarins and emperor tamarins respond to the playback of long calls from both conspecific group members and heterospecific tamarins with which they associate. Playback of long calls from heterospecific tamarins elicited long calls and approaches towards the speaker. These findings are consistent with the hypothesis that long calls serve as interspecific signals between associating tamarin species.

Abundance, diversity, and patterns of distribution of primates on the Tapiche River in Amazonian Peru.

This work presents data on the relative diversity, abundance, and distribution patterns of primates in a 20 km2 area of the Tapiche River in the Peruvian Amazon. Population data were collected while the study area was both inundated and dry (March to September 1997) using conventional line-transect census techniques. Survey results reflected the presence of 11 primate species, but population parameters on only eight of the species will be presented, including saddleback tamarins (Saguinus fuscicollis), Bolivian squirrel monkeys (Saimiri boliviensis), brown capuchins (Cebus apella), white-fronted capuchins (Cebus albifrons), monk sakis (Pithecia monachus), red titi monkeys (Callicebus cupreus), red uakaris (Cacajao calvus), and red howler monkeys (Alouatta seniculus). Woolly monkeys (Lagothrix lagotricha), night monkeys (Aotus nancymaae), and pygmy marmosets (Callithrix pygmaea) were also seen in the area. The data for the smaller-bodied primates is similar to that reported almost 18 years earlier, but the data for the larger-bodied primates reflect a loss in the number of animals present in the area. Pressure from hunters and the timber industry may account for declining numbers of large-bodied primates, while it appears that natural features peculiar to the conservation area contribute to the patchy pattern of distribution.

Subspecific genetic differences in the saddle-back tamarin (Saguinus fuscicollis) postcranial skeleton.

Saddle-back tamarins (Saguinus fuscicollis) have been differentiated into subspecies based on coat color and facial morphology. Morphology of first-generation genetic hybrids can provide an understanding of population differences and evolution that may otherwise be difficult to obtain. This study compares postcranial morphology in two hybrids of saddle-back tamarins (S. f. illigeri x S. f. lagonotus and S. f. illigeri x S. f. leucogenys) to the purebred subspecies. We examine whether postcranial morphology differs between the purebred subspecies and their hybrids, and whether hybrids exhibit heterosis indicative of genetic differences between the parental subspecies. Fifty postcranial dimensions, or traits, were measured on 287 S. fuscicollis skeletons. Measurements were corrected for sex differences and environmental differences (wild-derived or laboratory-born). Females were larger than males for most postcranial dimensions, especially in the pelvis. Significant environmental differences were found throughout the postcranial skeleton, with wild-derived animals generally larger than animals born in the laboratory. Significant heterosis was found for six postcranial traits in the S. f. illigeri x S. f. leucogenys cross, and heterosis was found for 15 postcranial traits in the S. f. illigeri x S. f. lagonotus cross. These results suggest that subspecies differences in skeletal morphology are generally due to genetic rather than environmental differences. The subspecies appear to represent geographic isolates that differ in gene frequencies and directional dominance for skeletal traits.

Patterns of positional behavior in mixed‐species troops ofCallimico goeldii,Saguinus labiatus, andSaguinus fuscicollisin northwestern Brazil

We present the results of a 4-month field investigation of positional behavior, vertical ranging, and species differences in limb proportions and body mass in a mixed-species troop of Saguinus fuscicollis, Saguinus labiatus, and Callimico goeldii in northwestern Brazil. Despite certain similarities in overall positional repertoire, patterns of positional behavior varied significantly between species. Travel in Callimico occurred principally in the lowest levels of the canopy, and was characterized by an exaggerated form of hindlimb-dominated bounding (bounding-hop), and leaping to and from vertical trunks (55.1% of leaps). In contrast, saddle-back tamarins traveled in the lower and middle levels of the canopy, and engaged in a range of leaping behaviors, including stationary leaps (37.3%), acrobatic leaps (31.3%), and trunk-to-trunk leaps (20%). Red-bellied tamarins exploited the highest levels of the arboreal canopy. Travel in this species was dominated by quadrupedal bounding and acrobatic leaps (67% of leaps) that began and ended on thin, flexible supports. Species differences in positional behavior correlated with species differences in limb proportions and locomotor anatomy, and provide a framework for understanding niche partitioning in mixed-species troops of Saguinus and Callimico.

Interspecific differences in prey captured by associating saddleback (Saguinus fuscicollis) and moustached (Saguinus mystax) tamarins

Interspecific differences in prey captured by associating saddleback (Saguinus fuscicollis) and moustached (Saguinus mystax) tamarins

Vertebrate predation by sympatric tamarins, Saguinus mystax and Saguinus fuscicollis.

Vertebrate predation was examined in sympatric moustached tamarins (Saguinus mystax) and saddle-back tamarins (Saguinus fuscicollis) in the Amazon rainforest of northeastern Peru. Both species prey on frogs and lizards, and very rarely on nestling birds. As a result of divergent foraging strategies, S. mystax primarily exploited frogs at higher strata of the forest, while S. fuscicollis predominantly preyed on reptiles in the lower strata and on the ground. This difference may strengthen the niche differentiation between these two tamarin species that exists with regard to other prey.

Infanticide in a group of wild saddle-back tamarins,Saguinus fuscicollis

An infanticide was observed in a group of wild saddle-back tamarins, Saguinus fuscicollis. The newborn singleton was killed by its mother after it had fallen from the carrier several times. This infanticide may represent a case of parental manipulation: the mother terminated investment in an offspring that probably had a low chance of survival. Also, stress associated with the simultaneous pregnancy of another adult female in the group may have played a role.

Infanticide in a group of wild saddle-back tamarins, Saguinus fuscicollis

Infanticide in a group of wild saddle-back tamarins, Saguinus fuscicollis

Infanticide in a group of wild saddle-back tamarins, Saguinus fuscicollis.

An infanticide was observed in a group of wild saddle-back tamarins, Saguinus fuscicollis. The newborn singleton was killed by its mother after it had fallen from the carrier several times. This infanticide may represent a case of parental manipulation: the mother terminated investment in an offspring that probably had a low chance of survival. Also, stress associated with the simultaneous pregnancy of another adult female in the group may have played a role.

Responses of Captive Single- and Mixed-Species Groups of Saguinus to Novel Nonthreatening Objects

The provision of novel objects allows one to probe for behavioural differences among species. This is particularly relevant when studying species that form mixed-species groups, as divergent responses may provide clues to the advantages that individuals gain from associating. We compared the responsiveness to novel objects in captive single- and mixed-species groups of saddleback (Saguinus fuscicollis) and red-bellied (Saguinus labiatus) tamarins to determine the influence of a congener. We tested groups with novel objects placed near the top, the middle, and on the floor of their enclosures and measured latency to approach and touch them. We tested predictions related to differences in lifestyle patterns under natural conditions. As we predicted, S.labiatus, which usually occur at a higher mean height in the forest than their congeners, responded to objects placed near the top of the enclosure significantly quicker in both single- and mixed-species groups. S. fuscicollis responded to objects placed on the floor quicker, and in mixed-species groups S. fuscicollis approached them before S. labiatus did. There were specific differences in median touch–approach time (T-A): Saguinus fuscicollis had a shorter T-A time than that of S. labiatus, which can be related to their manipulative foraging style. Reaction times decreased in mixed-species trials for both species, suggesting that the reaction of one species may effect the congener. Both species may benefit through association, though the dominance of Saguinus labiatus over S. fuscicollis may limit the advantages to S. fuscicollis. Over all our study supports the idea that cross-specific social facilitation is an important consequence of mixed-species groups of Saguinus.

Cloridrato de tiletamina associado com cloridrato de zolazepam na tranqüilização e anestesia de calitriquídeos (Mammalia, Primates)

Utilizou-se a associação de cloridrato de tiletamina (125mg) e cloridrato de zolazepam (125mg) diluídos em água destilada (10ml) como tranqüilizante e anestésico em 38 animais pertencentes às espécies Saguinus imperator imperator (N= 21), Saguinus fuscicollis weddeli (N= 15) e Cebuella pygmea (N=2). Indivíduos de ambos os sexos, com pesos entre 130 e 520g, receberam doses de 0,02ml (1,11mg/kg) a 0,15ml (8,33mg/kg) pela via intramuscular. Na maioria dos casos ocorreu anestesia. Os animais foram libertados no mesmo dia da captura, após recuperação pós-anestésica. Não ocorreu efeito colateral aparente sobre os fetos de duas fêmeas gestantes. Apesar da morte de um animal jovem, os resultados foram considerados satisfatórios na tranqüilização e anestesia de calitriquídeos.

Tamarin polyspecific associations: Forest utilization and stability of mixed-species groups

Niche separation is likely to play a key role in the formation of mixed-species groups. Saddle-backed tamarins (Saguinus fuscicollis) were studied at three sites with different primate communities in northern Bolivia: (1) with red-bellied tamarins,S. labiatus; (2) with emperor tamarins,S. imperator; and (3) without a congeneric species. The degree of association is higher betweenS. labiatus andS. fuscicollis than betweenS. imperator andS. fuscicollis and is related to differences in forest utilization between associating pairs. Niche separation is found to be greater betweenS. labiatus andS. fuscicollis than betweenS. fuscicollis andS. imperator. The mean height and habitat utilization ofS. fuscicollis does not differ greatly across the three sites, nor does the height of tamarins in and out of association. It is concluded that combined with differences in body size and dietary overlap, vertical segregation plays an important role in tamarin polyspecific associations (increasing the potential of both foraging and anti-predatory benefits) and that this is not a consequence of vertical displacement ofS. fuscicollis by its dominant congeners.