Cebus

Evidence for paternal kin recognition and paternally biased behaviors is mixed among primates. We investigate whether infant handling behaviors exhibit paternal kin biases in wild white-faced capuchins monkeys (Cebus capucinus) by comparing interactions between infants and genetic sires, potential sires, siblings (full sibling, maternal, and paternal half-siblings) and unrelated handlers. We used a linear mixed model approach to analyze data collected on 21 focal infants from six groups in Sector Santa Rosa, Costa Rica. Our analyses suggest that the best predictor of adult and subadult male interactions with an infant is the male's dominance status, not his paternity status. We found that maternal siblings but not paternal siblings handled infants more than did unrelated individuals. We conclude that maternal but not paternal kinship influence patterns of infant handling in white-faced capuchins, regardless of whether or not they can recognize paternal kin. Am. J. Primatol. 78:6...

The present work is part of a decade-long study on the spontaneous use of stones for cracking hard-shelled nuts by a semi-free-ranging group of brown capuchin monkeys (Cebus apella). Nutcracking events are frequently watched by other individuals - usually younger, less proficient, and that are well tolerated to the point of some scrounging being allowed by the nutcracker. Here we report findings showing that the choice of observational targets is an active, non-random process, and that observers seem to have some understanding of the relative proficiency of their group mates, preferentially watching the more skilled nutcrackers, which enhances not only scrounging payoffs, but also social learning opportunities.

The representation of the two eyes in striate cortex (V1) ofCebus monkeys was studied by electrophysiological single-unit recordings in normal animals and by morphometric analysis of the pattern of ocular dominance (OD) stripes, as revealed by cytochrome oxidase histochemistry in V1 flat-mounts of enucleated animals. Single-unit recordings revealed that the large majority of V1 neurons respond to the stimulation of either eye but are more strongly activated by one of them. As in other species of monkey, neurons with preference for the stimulation of the same eye are grouped in columns 300–400 µm wide, spanning all cortical layers. Monocular neurons are clustered in layer IVc, specially in its deeper half (IVc-beta), and constitute less than 10% of the population of other layers. Neurons with equal responses to each eye are more commonly found in layer V than elsewhere in V1. In the supragranular layers and in granular layer IVc-alpha neurons strongly dominated by one of the eyes tend to be broadly tuned for orientation, while binocularly balanced neurons tend to be sharply tuned for this parameter. No such correlation was detected in the infragranular layers, and most neurons in layer IVc-beta responded regardless of stimulus orientation. Ocular dominance stripes are present throughout most of V1 as long, parallel or bifurcating bands alternately dominated by the ipsi- or the contralateral eye. They are absent from the cortical representations of the blind spot and the monocular crescent. The domains of each eye occupy nearly equal portions of the surface of binocular V1, except for the representation of the periphery, where the contralateral eye has a larger domain, and a narrow strip along the border of V1 with V2, where either eye may predominate. The orderliness of the pattern of stripes and the relationship between stripe arrangement and the representation of the visual meridians vary with eccentricity and polar angle but follow the same rules in different animals. These results demonstrate that the laminar, columnar and topographic distribution of neurons with different degrees of OD in V1 is qualitatively similar in New- and Old World monkeys of similar sizes and suggest that common ancestry, rather than parallel evolution, may account for the OD phenotypes of contemporaneous simians.

It has been known for 40 years that dietary saturated fat (SAT FAT) increases plasma cholesterol, including LDL-C and HDL-C. In humans, where LDL-C is typically > 90 mg/dl this SAT FAT effect largely reflects changes in LDL-C pool size. The original human studies suggested that LDL-C expansion during SAT FAT consumption reflected reduced LDL clearance (LDL receptor activity) in hyperlipemics and increased LDL production rates in normolipemics (LDL-C < 100 mg/dl). This dual explanation is supported by data from several animal models where specific saturated fatty acids (SFAs) have been the focus. However, the situation is complicated by the fact that polyunsaturated fatty acids (PUFAs) oppose SFAs, i.e. PUFAs decrease LDL-C and increase LDL receptor (LDLr) activity, so the effect of SAT FAT intake may represent the combined influence of increased SFAs and decreased PUFAs. In fact, careful scrutiny of primate data suggests a negligible effect of saturated fat on LDL clearance (and receptor activity) in the absence of dietary cholesterol when PUFA intake is adequate (5–10%en) and the lipoprotein profile is relatively normal (LDL-C < 90 mg/dl), i.e. normolipemic situations at the time of dietary intervention. In such cases increases in LDL-C due to SFAs (particularly 12:0+14:0) appear to reflect LDL overproduction associated with a shift in cholesterol from tissues to the plasma cholesteryl ester (CE) pool (both LDL-C and HDL-C) without altering whole-body cholesterol balance. The reason for this shift, which is accompanied by an increase in the plasma oleic/linoleic CE ratio, is unknown but may reflect a decreased rate of CE hydrolysis by the liver. When individuals or animals are rendered hyperlipemic by other factors (e.g. chronic caloric and dietary cholesterol excesses in humans or by cholesterol feeding in animals) specific SFAs (particularly 16:0) can contribute to decreased LDLr activity initiated by a primary factor, such as dietary cholesterol. However, LDLr down-regulation by dietary cholesterol greatly exceeds any contribution from SFAs.

We have prepared five new analogs (n-propyl, iso-propyl, allyl, n-butyl, and iso-butyl) of the dopamine D-2 receptor antagonist, FPMB which result from modifications of the ethyl group at the pyrrolidine nitrogen in FPMB. As expected, all new derivatives showed higher apparent lipophilicity (log kw), with iso-butyl being the most lipophilic (log kw = 2.52), followed by the allyl derivative (log kw = 2.43). The allyl group showed the largest increase in affinity (from 0.26 nM for the ethyl substituent to 0.03 nM for the allyl substituent, almost 10-fold), followed by the n-propyl substituent which showed approximately five-fold better affinity than did the ethyl substituent. Radiosynthesis of (S)-N-[(1-allyl-2-pyrrolidinyl)methyl]-5-(3-[18F]fluoropropyl)-2, 3-dimethoxybenzamide ([18F]fallypride) was carried out by nucleophilic substitution reaction of (S)-N-[(1-allyl-2-pyrrolidinyl) methyl]-5-(3-tosyloxypropyl)-2,3-dimethoxybenzamide with no carrier added 18F-. [18F]Fallypride was ob...

Large-field trichromacy is a general feature of protanope and deuteranope humans, provided that the stimuli size extends to an 8° visual angle. In this study we compared the performance of five male and three female tufted capuchin monkeys (Cebus apella) in discriminating pairs of Munsell color papers. Human subjects were also studied in two-choice discrimination tests, using the same stimuli and apparatus employed for the monkeys. The results show that although the dichromatic humans showed improved discrimination with larger versions of the stimuli, the dichromatic monkeys exhibited the same performance for both stimuli sizes. Thus, Cebus apella apparently do not present large-field trichromacy-at least for the conditions in the present experiments. Am. J. Primatol. 67:437–446, 2005. © 2005 Wiley-Liss, Inc.

The threat of predation can significantly influence prey behaviors through altered perceptions of risk. Prey risk perception is constantly updated via collection of personal and social information about predators. Better understanding of the links between information availability, its use, and prey species&#39; perception of risk will aid in explaining how animals adapt to predation. The goal of this study was to determine the environmental and social cues-available to prey via personal and social information, respectively-that influence wild squirrel monkey (Saimiri sciureus) reactivity to potential predators, treated here as a proxy for risk perception. We followed squirrel monkey troops for 3 years in Suriname, South America, and accounted for environmental and social variables associated with potential predator encounters. We utilized logistic regression models applied to a robust and long-term data set to reveal relationships among factors affecting squirrel monkey anti-predato...

This study reports a case of parasitism by Dioctophyma renale (Goeze, 1762) encysted in the abdominal cavity of a capuchin monkey (Cebus apella) coming from the Centro Nacional de Primatas, Brazil. The animal was sent to the Veterinary Clinic sector with an increase in abdominal volume and no occurrence of any other clinical signs. Upon palpation, a movable circular mass with a diameter of approximately 10 cm was found. Urinalysis, complete blood count and serum biochemistry were performed without revealing any alterations. The animal was then submitted to an abdominal ultrasound exam. The cyst was punctured and a surgical removal procedure was performed, revealing a brownish-colored cylindrical structure that was already deteriorated, making it impossible to perform morphological analysis and classification. In the sediment of the liquid found, eggs were encountered that had morphological characteristics compatible with D. renale. The objective of this paper is to report the first case of parasitism by D. renale in C. apella (Linnaeus, 1758).

This article is the final report of the ABLE (Action, Brain, Language, Evolution) mini-workshop on “Construction, Tools and Language” held at Emory University, Atlanta, November 2019. The paper approaches tool use, construction and language within a new framework for comparative biology and psychology studies that builds on neuroethological studies of action-oriented perception in relation to human manual skills, preconditions and postconditions for action, tooling, distalization in space (distalization of the end effector) and time (current actions may serve distal goals), and a view of affordances that incorporates elements of Gibson’s ecological psychology, but in a way that explores their possible titration against cognitive processes. The diverse applicability of this framework is exemplified by analysis of nut cracking by monkeys, of Oldowan and Acheulean stone tool making as examples of subtractive construction, and of nest-building by birds and construction of hafted tools as examples of additive construction. Language is assessed as a process of mental construction and comprehension and related to manual skills by the technological pedagogy hypothesis and the mirror system hypothesis.