Captive Capuchin Monkeys Research Articles

Copying without rewards: socially influenced foraging decisions among brown capuchin monkeys

An individual's foraging activity can be influenced by the choices made by nearby conspecifics. The interest shown in the location and characteristics of a feeding patch may depend on the feeding success of a conspecific there, a process that needs to be distinguished from choices guided by rewards to the observer itself. We investigated how rewards for both self and others influence the foraging choices of captive capuchin monkeys (Cebus apella). Thirteen adult capuchins observed familiar female conspecific models explore one of three opaque boxes under three conditions. In the first, there were no rewards available to either monkey; in the second, rewards were available to the model only; and in the third, both monkeys could retrieve a reward. Under all conditions, subjects more often explored the same box as the model than was expected by chance. Thus, without ever receiving a reward themselves or without seeing another receive rewards, subjects' searches were directed at the box explored by another monkey. The tendency to match the model's choice increased if the subject was rewarded. We compared these results to control conditions in which the model was either absent, or present but not allowed to demonstrate. Subjects' located the reward less often in control conditions, than in the experimental conditions. We conclude that extrinsic rewards, while helpful, are not required for partners to influence the foraging choices of capuchins, and that the unrewarded copying of foraging choices demonstrated here may provide the basis for additional social influences on learning.

How tufted capuchin monkeys (Cebus apella) rank monkey chow in relation to other foods

AbstractCaptive primates are usually fed on monkey chow, a high-energy food designed to provide a complete and balanced diet for primates. In addition to the nutritional value of a food, its palatability, frequency of presentation in the daily diet and sensory stimulation may also be important for determining whether it is accepted by the animals. The aim of this study was to evaluate the food preferences of 26 captive capuchin monkeys (Cebus apella) using monkey chow and a variety of foods, which ranged from being very familiar to completely novel to the monkeys, and to assess whether the frequency of presentation in the daily diet and sensory stimulation affected their food preferences. Food preferences were scored in terms of the food item chosen and whether it was then eaten. In Experiment 1, subjects encountered paired combinations of seven familiar foods (present in the monkeys' diet with different frequencies), including monkey chow. In Experiments 2 and 3, monkey chow was paired with seven novel foods (not previously present in the monkeys' diet) and seven ex-novel foods (previously only encountered repeatedly during an earlier experiment) respectively. The results show that monkey chow, despite its high energy content, was not very attractive to capuchin monkeys. Other familiar foods (especially those not presented daily) were chosen and eaten more frequently than the monkey chow, and novel foods were chosen more frequently than the monkey chow. The findings of this study have implications for the feeding husbandry of captive primates. Familiar foods presented in the diet each day are less preferred; therefore good practice would be to alternate foods over time. Occasional presentation of novel food items could be a stimulating and economical method of providing sensory enrichment.

Hematological values of Cebus apella anesthetized with ketamine

Blood samples were collected from 124 captive Capuchin monkeys (Cebus apella) at Fundacao Parque Zoologico de Sao Paulo, anesthetized with ketamine (10 mg/kg, IM). Hematological parameters (RBC, WBC, differential count, hematocrit, hemoglobin, MCV, MCH and MCHC) were determined, and influence of sex and age on hematologic values was studied.

The stone‐tool technology of capuchin monkeys: Possible implications for the evolution of symbolic communication in hominids

Abstract Research with captive capuchin monkeys has demonstrated that these New World primates produce flaked stone artifacts that they use as cutting tools, and that they exhibit patterns of right‐handedness analogous to those of tool‐making Plio‐Pleistocene hominids. These findings indicate that the cognitive and biomechanical conditions of pre‐adaptation for the production and use of stone tools are present in extant nonhuman primates, and that capuchins can be used to model processes associated with the evolution of technology and symbolic communication in humans.

Acquisition of Nut-Cracking Behaviour by 2 Capuchin Monkeys (Cebus apella)

The acquisition of nut-cracking behaviour was investigated in two naive groups of captive capuchin monkeys (Cebus apella). Two adult males acquired this behaviour independently and without any ad hoc training. The opportunity to freely explore and manipulate the ‘hammers’ favoured the discovery of the correct and successful spatial relationship between the nut and the tool. The other group members did not seem to learn the use of tools either independently or by observing their proficient cagemates.

Effects of manipulatable objects on the activity of captive capuchin monkeys (Cebus apella)

AbstractThe aim of this study was to evaluate simple behavioral enrichment procedures for a captive group of tufted capuchin monkeys (Cebus apella). We examined the effects of providing a manipulatable substrate (straw) and a variety of portable objects in the monkeys' home cage. The animals were observed across three conditions in two replications: 1) No portable objects were present; 2) a set of six identical portable objects was present; and 3) a set of six varied portable objects was present. The cage floor was bare in the first replication; straw was uniformly spread on the cage floor in the second replication. An 18‐month period of qualitative note taking followed completion of the initial data collection phase.The presence of straw and portable objects affected patterns of affiliation by decreasing quiet contact and close proximity. Providing additional manipulative opportunities affected both the form and frequency of object‐directed activities. Object contacts were directed toward a greater variety of targets, and some objects were spontaneously used as tools. Manipulation of provided objects and use of objects as tools have become routine activities in this group of monkeys. We conclude that providing straw and portable objects in an already well equipped cage is an effective means of long‐term behavioral enrichment for captive capuchin monkeys. Enabling captive capuchins to express species‐typical manipulative tendencies is apparently conducive to the monkeys' optimal physical and psychological well‐being as well as interesting to the human observer.