Professional Affiliations and Activities
Member, American Society of Primatologists (2010 - Present)
Cup tool use by squirrel monkeys
AMERICAN JOURNAL OF PRIMATOLOGY
2015; 77 (12): 1323-1332
Captive-born male and female squirrel monkeys spontaneously 'invented' a cup tool use technique to Contain (i.e., hold and control) food they reduced into fragments for consumption and to Contain water collected from a valve to drink. Food cup use was observed more frequently than water cup use. Observations indicate that 68% (n?=?39/57) of monkeys in this population used a cup (a plastic slip cap) to Contain food, and a subset of these monkeys, 10% (n?=?4/39), also used a cup to Contain water. Cup use was optional and did not replace, but supplemented, the hand/arm-to-mouth eating and direct valve drinking exhibited by all members of the population. Strategies monkeys used to bring food and cups together for food processing activity at preferred upper-level perching areas, in the arboreal-like environment in which they lived, provides evidence that monkeys may plan food processing activity with the cups. Specifically, prior to cup use monkeys obtained a cup first before food, or obtained food and a cup from the floor simultaneously, before transporting both items to upper-level perching areas. After food processing activity with cups monkeys rarely dropped the cups and more often placed the cups onto perching. Monkeys subsequently returned to use cups that they previously placed on perching after food processing activity. The latter behavior is consistent with the possibility that monkeys may keep cups at preferred perching sites for future food processing activity and merits experimental investigation. Reports of spontaneous tool use by squirrel monkeys are rare and this is the first report of population-level tool use. These findings offer insights into the cognitive abilities of squirrel monkeys and provide a new context for behavior studies with this genus and for comparative studies with other primates. Am. J. Primatol. © 2015 Wiley Periodicals, Inc.
View details for DOI 10.1002/ajp.22486
View details for Web of Science ID 000363892500008
View details for PubMedID 26436899
Echocardiographic and Electrocardiographic Characteristics of Male and Female Squirrel Monkeys (Saimiri spp.).
Journal of the American Association for Laboratory Animal Science
2015; 54 (1): 25-28
Cardiomyopathy is a leading cause of mortality in aging squirrel monkeys (Saimiri spp.). However, data regarding echocardiographic measures obtained from clinically healthy nonsedated squirrel monkeys have not been published, and few electrocardiographic data are available. Here we obtained echocardiographs without sedation and electrocardiographs with minimal sedation from 63 clinically healthy squirrel monkeys that ranged from 3 to 20 y in age. 2D and M-mode echocardiography were performed on nonsedated monkeys to determine the left ventricular internal diameters at systole and diastole and the ejection fraction. Electrocardiography was performed under sedation with ketamine (15 mg/kg). Parameters evaluated included heart rate; P-wave duration; lengths of the PR, QRS, and QT intervals; R-wave amplitude, and P-wave amplitude. Initial physical examination, electrocardiography, and echocardiography indicated normal cardiac function for all monkeys. The objectives of this study were to provide reference values for nonsedated echocardiography and ketamine-sedated electrocardiography of clinically normal squirrel monkeys and to determine correlates of age and sex in these values.
View details for PubMedID 25651087
A novel form of oxytocin in New World monkeys
2011; 7 (4): 584-587
Oxytocin is widely believed to be present and structurally identical in all placental mammals. Here, we report that multiple species of New World monkeys possess a novel form of oxytocin, [P8] oxytocin. This mutation arises from a substitution of a leucine to a proline in amino acid position 8. Further analysis of this mutation in Saimiri sciureus (squirrel monkey) indicates that [P8] oxytocin is transcribed and translated properly. This mutation is specific to oxytocin, as the peptide sequence for arginine vasopressin, a structurally related nonapeptide, is unaltered. These findings dispel the notion that all placental mammals possess a 'universal' oxytocin sequence, and highlight the need for research on the functional significance of this novel nonapeptide in New World monkeys.
View details for DOI 10.1098/rsbl.2011.0107
View details for PubMedID 21411453
Early life stress and novelty seeking behavior in adolescent monkeys
2007; 32 (7): 785-792
Recent evidence suggests that early exposure to mild stress promotes the development of novelty seeking behavior. Here we test this hypothesis in squirrel monkeys and investigate whether novelty seeking behavior is associated with differences in cerebrospinal fluid (CSF) levels of the serotonin metabolite 5-hydroxyindoleacetic acid (5HIAA), the dopamine metabolite homovanillic acid (HVA), the norepinephrine metabolite 3-methoxy-4-hydroxyphenylethylene glycol (MHPG), and the neuropeptide corticotrophin-releasing factor (CRF). Monkeys were randomized early in life to either mild intermittent stress (IS) or no stress (NS) conditions, and subsequently presented with opportunities to interact with a familiar or novel object in a test box that was connected to each monkey's home cage. To further minimize the potentially stressful nature of the test situation, monkeys were acclimated to the test procedures prior to study initiation. Post-test plasma levels of cortisol in IS and NS monkeys did not differ significantly from baseline levels measured in undisturbed conditions. During testing, more IS than NS monkeys voluntarily left the home cage, and IS monkeys spent more time in the test box compared to NS monkeys. More IS than NS monkeys engaged in object exploration in the test box, and IS monkeys preferred to interact with the novel vs. familiar object. Novelty seeking was not associated with differences in 5HIAA, HVA, MHPG, or CRF, but correlated with differences in object exploration observed in a different test situation at an earlier age. These trait-like differences in novelty seeking appear to reflect mild early stress-induced adaptations that enhance curiosity and resilience.
View details for DOI 10.1016/j.psyneuen.2007.05.008
View details for Web of Science ID 000249510200003
View details for PubMedID 17604913
View details for PubMedCentralID PMC2716798
Maternal mediation, stress inoculation, and the development of neuroendocrine stress resistance in primates
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
2006; 103 (8): 3000-3005
The stress inoculation hypothesis presupposes that brief intermittent stress exposure early in life induces the development of subsequent stress resistance in human and nonhuman primates. Rodent studies, however, suggest a role for maternal care rather than stress exposure per se (i.e., the maternal mediation hypothesis). To investigate these two hypotheses, we examined maternal care and the development of stress resistance after exposure to brief intermittent infant stress (IS), mother-infant stress (MIS), or no stress (NS) protocols administered to 30 monkeys between postnatal weeks 17 and 27. Unlike rodents, the IS condition did not permanently increase primate maternal care, nor did measures of total maternal care predict subsequent offspring hypothalamic-pituitary-adrenal-axis responsivity. Although MIS infants received less maternal care than IS and NS infants, both IS and MIS monkeys developed subsequent stress resistance. These findings indicate that rearing differences in the development of stress resistance are more closely related to differences in prior stress exposure than to differences in maternal care. A second experiment confirmed this conclusion in a different cohort of 25 monkeys exposed as infants to high foraging-demand (HFD) or low foraging-demand (LFD) conditions. HFD infants exhibited intermittent elevations in cortisol levels and received less maternal care than LFD infants. In keeping with a key prediction of the stress inoculation hypothesis, HFD males responded to stress in adulthood with diminished hypothalamic-pituitary-adrenal-axis activation compared with LFD males. Results from both experiments demonstrate that stress inoculation, rather than high levels of maternal care, promotes the development of primate stress resistance.
View details for DOI 10.1073/pnas.0506571103
View details for Web of Science ID 000235554900093
View details for PubMedID 16473950
View details for PubMedCentralID PMC1413772