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Introduction Food insecurity is a major global contributor to developmental origins of adult disease. The allostatic load of maternal food uncertainty from variable foraging demand (VFD) activates corticotropin-releasing factor (CRF) without eliciting hypothalamic-pituitary-adrenal (HPA) activation measured on a group level. Individual homeostatic adaptations of the HPA axis may subserve second-order homeostasis, a process we provisionally term “social allostasis.” We postulate that maternal food insecurity induces a “superorganism” state through coordination of individual HPA axis response. Methods Twenty-four socially-housed bonnet macaque maternal-infant dyads were exposed to 16 weeks of alternating two-week epochs of low or high foraging demand shown to compromise normative maternal-infant rearing. Cerebrospinal fluid (CSF) CRF concentrations and plasma cortisol were measured pre- and post-VFD. Dyadic distance was measured, and blinded observers performed pre-VFD social ranking assessments. Results Despite marked individual cortisol responses (mean change = 20%) there was an absence of maternal HPA axis group mean response to VFD (0%). Whereas individual CSF CRF concentrations change = 56%, group mean did increase 25% (p = 0.002). Our "dyadic vulnerability" index (low infant weight, low maternal weight, subordinate maternal social status and reduced dyadic distance) predicted maternal cortisol decreases (p < 0.0001) whereas relatively “advantaged” dyads exhibited maternal cortisol increases in response to VFD exposure. Comment In response to a chronic stressor, relative dyadic vulnerability plays a significant role in determining the directionality and magnitude of individual maternal HPA axis responses in the service of maintaining a “superorganism” version of HPA axis homeostasis, provisionally termed “social allostasis.”

Objectives: Macaques are used in cardiovascular and metabolic research. We determined echocardiographic-derived reference values of left ventricular (LV) systolic and diastolic function in healthy adult bonnet macaques (Macaca radiata). Methods: Transthoracic echocardiography was performed during ketamine sedation in 83 (67% female) healthy monkeys (age 7–26 years). Results: Technically adequate studies were obtained in all subjects and required 10.1 ± 1.3 min of scanning time. Age correlated inversely with the following Doppler indices: E (r = –0.44, p < 0.001), E/A (r = –0.26, p = 0.02), E′ (r = –0.45, p < 0.001, E′/A′ (r = –0.44, p < 0.001), E/E′ (r –0.25, p = 0.03), S′ (r = –0.33, p = 0.003), Vp (r = –0.26, p = 0.049). LV mass was more strongly correlated with crown rump length (r = 0.72, p < 0.001) and body surface area (r = 0.70, p < 0.001) than with body mass index (r = 0.47, p < 0.001) and weight (r = 0.63, p < 0.001). Conclusions: This study demonstrates echocardiography is feasible for characterizing LV function. Age-related changes in Doppler indices in primates are similar to those in humans. LV mass is more closely related to fat-free mass indices. We provide reference values for LV systolic and diastolic function in adult bonnet macaques across the captive life span.

Background Long-term behavioral, immunologic, and neurochemical alterations have been found in primates exposed to adverse early rearing. Methods Bonnet macaque ( Macaca radiata ) mother–infant dyads were exposed to uncertain requirements for food procurement (variable foraging demand, VFD) for a few months. Ten years later, these offspring and age- and gender-matched control subjects were studied using proton magnetic resonance spectroscopic imaging (MRSI). Results In anterior cingulate, VFD-reared subjects displayed significantly decreased N -acetylaspartate (NAA) resonance and significantly increased glutamate–glutamine–γ-aminobutyric acid (Glx) resonance relative to the stable neurometabolite creatine (Cr). Across all subjects, NAA/Cr and Glx/Cr ratios in the anterior cingulate were negatively correlated ( r = −.638, p = .014). In the medial temporal lobe, the ratio of choline-containing compounds to Cr was significantly increased in VFD subjects. Conclusions These findings indicate that adverse early rearing in primates has an enduring impact on adult MRSI measures considered reflective of neuronal integrity and metabolism, membrane structure and glial function, and cerebral glutamate content, and that these alterations occur in the same brain regions implicated in trauma-related psychiatric disorders.

The two neuropeptides corticotropin-releasing-factor (CRF) and oxytocin (OT) may produce opposing behavioral effects — elevations of the former have been associated with anxiety and social vigilance and reductions of the latter with reduced social affiliation. We sought to test the hypothesis that, within the primate macaque genus, the more gregarious, affiliative, and affectively stable bonnet species ( Macaca radiata ) would exhibit lower cerebrospinal fluid (CSF) CRF and higher CSF OT concentrations in comparison to its close relative, the temperamentally volatile and socially distant pigtail ( Macaca nemestrina ). Cisternal CSF samples were obtained from young adult male and female pigtail and bonnet macaques, and CRF and OT concentrations were measured by radioimmunoassay. Pigtail macaques exhibited significantly higher concentrations of CSF CRF and significant lower concentrations of CSF OT than bonnet macaques. Results were not attributable to age or sex differences in group composition. When included together in a multiple regression, CRF and OT showed a multiple R of 0.76, accounting for more than half of the species variance. Although species differences in the bioeffectiveness of these peptides may possibly confound the observed biobehavioral relationships, in the absence of any existing data to that effect, the current findings appear in accordance with the hypothesis and consistent with previously reported species–typical behaviors observed in these macaques.

Adolescent bonnet macaques nursed as infants by mothers facing unpredictable requirements for food procurement (variable foraging demand, VFD) display persistent neurobiological disturbances. This study examined the long-term neurochemical and behavioral effects of adverse rearing initiated later in infancy than in previous cohorts of subjects to test the hypothesis that the timing of an early adverse experience would influence patterns of biobehavioral outcome. Cisternal cerebrospinal fluid (CSF) monoamine and corticotropin-releasing factor (CRF) concentrations were obtained from 20 bonnet macaques (11 VFD-reared and 9 normally reared controls) approximately 2 years after the end of differential rearing. VFD-reared primates displayed on multiple samplings significantly lower CSF CRF concentrations and higher CSF 5-hydroxyindoleacetic acid (5-HIAA) concentration compared to controls. In the VFD-reared, significant inverse correlations between CRF and all three monoamines were found (5-HIAA, 3-methoxy-4-hydroxyphenethyleneglycol and homovanillic acid), most prominently for 5-HIAA. In controls, but not VFD-reared subjects, CSF CRF was positively correlated with changes in "gregariousness" upon presentation of a fear stimulus. VFD-reared subjects displayed greater baseline hierarchical engagement than controls. In contrast to prior findings, in which rearing under VFD conditions at an earlier age led to increased CSF CRF compared with controls, CSF CRF was lower after later exposure to VFD rearing than in controls. Thus, the timing of exposure to VFD conditions early in life evidently determines whether CSF CRF was found to be elevated or decreased, within the context of increased serotonin metabolism, during the course of primate maturation.

When primate infants are reared during the first half-year of life in an environment in which their mothers face uncertain requirements for food procurement (variable foraging demand [VFD]), long-lasting behavioral and neurodevelopmental consequences ensue, including increases in timidity and social subordinance as well as alterations in stress-related neuroendocrine profiles. We examined the nature and persistence of the effects of VFD rearing by exposing VFD-reared and normally reared adolescent bonnet macaques to a mild fear-provoking stimulus 2 years after the end of differential rearing. VFD-reared subjects at baseline were less gregarious than normally reared monkeys. VFDs also were considerably less responsive to the fear stimulus, and their behavior and affect returned to baseline levels more quickly than normally reared subjects. The extent and persistence of the sequelae of VFD rearing suggest parallels with predisposing factors in human anxiety disorders. © 2001 John Wiley & Sons, Inc. Dev Psychobiol 39: 40–45, 2001

The video-task paradigm has been suggested as a means of providing enrichment for laboratory primates. The purpose of this study was to investigate the effect of providing multiple devices to socially housed pigtail macaques. Using different cage locations, the subjects were tested with conditions of access to a single device and with access to three identical devices. Differential preference among locations was strongly evident, but only when multiple devices were simultaneously accessible. Although a single device was never used to its theoretical maximum potential, overall device utilization was significantly higher with multiple devices available. Provision of a perch that equalized the substrate at all locations diminished, but did not eliminate, differential preference among locations.

The diurnal pattern of joystick use by five individually caged bonnet macaque monkeys ( Macaca radiata ), with continuous access to a computer-controlled joystick task that required contacting a small stationary target with the cursor, was characterized by a dramatic peak occurring between 1500 and 1700 h and little activity during the morning hours. With 2 h limited daily access pseudorandomly scheduled across days, a similar pattern was found, although the number of trials completed during 2-h intervals of limited access was greater than that during the same intervals of continuous access. When an extended period of access at a fixed time each morning was compared to a similar period of fixed access time in the afternoon, the afternoon continued to be characterized by significantly higher levels of use.

A microchip that provided a unique identification number was injected into each forearm of all 8 members of a bonnet macaque (Macaca radiata) social group. The group was then given computer-controlled joystick tasks of increasing difficulty. The identification number of the arm used on each trial was input into the computer and used to determine individual performance and hand preference in more than 23,000 trials. Three subjects reversed hand preference as task difficulty was increased over time. All subjects exhibited nearly exclusive use of a single hand on the most difficult task; 6 used the right hand, and 2 used the left. Daily patterns of joystick activity for the group members differed somewhat from that of our individually housed monkeys.

To assess the developmental consequences of rearing environments for 12 infant bonnet macaques (Macaca radiata), infants from 2 environments, either low foraging demand (LFD) or variable foraging demand (VFD) for their mothers, were observed under 2 test conditions after the completion of the differential rearing treatment. One of the test conditions involved introduction of the rearing cohorts to a novel room; this was done in two series of four 1-hr sessions, a series before and a series after completion of the 2nd test condition. The 2nd test condition involved a 20.5-hr removal of each mother from the rearing cohort; this was repeated once a week for 3 weeks. The results of the novel room tests effectively differentiated rearing treatments in this study and suggested treatment group differences in attachment security. In contrast, the maternal separations failed to differentiate rearing treatments.

12 bonnet macaque (Macaca radiata) mother-infant dyads were studied. For 14 weeks, beginning when the infants were a mean age of 11.2 weeks, the dyads were housed and observed under different foraging-demand conditions for the mothers: 6 dyads in a low-foraging-demand (LFD) condition and 6 dyads in a variable-foraging-demand (VFD) conditions. For VFD mothers, demand varied between low and high in 2-week blocks. Differences between the LFD and VFD groups were minimal during this period; there was, however, more maternal grooming and shorter separation bouts in the VFD group than in the LFD group. The dyads were then challenged by brief introductions to a novel environment. The challenge revealed that frequency of breaking dyadic contact and levels of play were significantly lower for the VFD infants than for the LFD infants, perhaps as a consequence of less secure attachment.

The maternal stress response may vary as a function of infant developmental phase. Using a median split, 13 bonnet macaque (M. radiata) mother-infant dyads were exposed to early initiation of variable foraging demand (VFD), a prolonged stressor, whereas 11 dyads were exposed to late VFD onset. Cerebrospinal fluid (CSF) and plasma samples were obtained from mothers and infants prior to and following VFD. Increases in maternal CSF corticotropin-releasing factor (CRF) concentrations were evident in response to late, but not early, VFD. Mothers exhibited either increased or decreased cortisol concentrations in response to VFD. However, absolute cortisol change was greater in early versus late VFD. Timing of the VFD stressor differentially affects maternal neuroendocrine response, with potential implications for the offspring's developmental trajectory.

Obesity has negative health consequences related to fat distribution, particularly the central or visceral accumulation of fat. The major complications associated with visceral obesity, termed the “Metabolic Syndrome of Obesity,” or “Syndrome X,” are type II diabetes, hypertension, and dyslipidemia. As with certain mood disorders, the syndrome may be a consequence of neuroendocrine perturbations typically associated with chronic stress. Our work with bonnet macaque monkeys provides an animal model for the relationship between early stress, behavioral and hypothalamic-pituitary-adrenal (HPA) axis dysregulation, and Syndrome X. During their infant's first half-year, mothers face a variable foraging demand (VFD), in which ample food varies unpredictably in the difficulty of its acquisition, and the offspring show persistent abnormalities in systems known to modulate stress and affective regulation. Early work on the bonnet macaque noted the emergence of a sample of spontaneously obese subjects as they matured. Using the VFD model, the current study showed that there was a clear relationship between early cerebrospinal fluid corticotropin-releasing factor levels and subsequently measured body mass index, supporting the hypotheses regarding the interactive roles of early experience and HPA axis dysregulation in the ontogeny of both metabolic and mood disorders.

Three individually housed bonnet macaque males were given 75 weeks of continuous access to a joystick task with a reward choice of either viewing live color video of a bonnet group or obtaining a banana-flavored food treat. Here we report data for weeks 44-75 following a change in the stimulus group displayed in the video. The new stimulus group enhanced responding to the video for two subjects over the entire 32 weeks of this study, although there was some decline across weeks, and the video continued to be an effective reward for the duration of the study for all subjects.

Summary.-Two groups of bonnet macaque (Maraca radiato) mother-infant dyads were exposed to 12 wk. of a variable foraging demand paradigm for the mothcrs beginning when the infants were approximately 18 weeks of age. For the nursery group, infants were required to remain in a nursery within the mothers' living area during the entire treatment period. Testing of the dyads of both groups in a novel room subsequent to the differential rearing experience showed that only the inhnts required to remain within the nursery exhibited an increase in motor engagement of the novel environment over the first hour of exposure, possibly reflecting greater security of ;lttachment in these nursery infants. We previously demonstrated that a foraging task for bonnet macaque (Maraca radiata) mothers that varies benveen easy and difficult for 2-wk. blocks (variable foraging demand) during early infant development results in reduced motor engagement of a novel environment by the infants in subsequent testing and suggests a reduced security of attachment by comparison to infants reared by mothers with a low foraging demand (2, 3). To clarlfy mechanisms in this effect, we also developed a contact-permissive-mesh nursery that allows us to operationalize when mothers have made themselves available to their infants for grooming, huddling, etc., i.e., at the nursery, and permits us to provision the infants selectively, thereby buffering them from the direct effects of the foraging demands (4). The present goal was to assess how nursery rearing might modb the impact of variable foraging demand on infants' behavioral patterns in a novel environment subsequent to the experimental rearing condition. The nursery rearing might increase the effects because dyadic interactions would have to be negotiated through mesh, and mother would be physically unavailable during the necessary periods of task engagement. However, because the nursery rearing allows mothers to choose when to make themselves physically available to their infants, they may be psychologitaUv available at the same time. Concordance of physical and psychological availabilities may be I11ghc.r the more positive the overall quality of dyadic interactions with a lesser Wtelihood of hsrr~cl~on or rejection. This in turn would promote more secure infant development and mitigate the effects of variable foraging demand.

The effect of social context on experimental foraging in squirrel monkeys (Saimiri sciureus) was investigated. The 12 subjects comprised six pairs in which strong social preference and attraction had been demonstrated during observations of a stable group. Individuals were first trained to discriminate spatially separated rich and poor foraging bins containing 75% and 25% of the food items, respectively, with their partners restrained equidistant from the two bins. The monkeys invested an average of 75.5% of their foraging time in the rich bin. Each individual was then tested with its partner restrained in different locations relative to the bins to determine the effect of partner proximity on foraging patterns. Foraging efficiency at the start of a session was enhanced when the partner was restrained adjacent to the rich bin compared to restraint away from this bin. Over an entire foraging session, however, all conditions providing partner accessibility were similar in yielding enhanced foraging efficiency compared to partner absence. Little time was spent in close physical proximity to the partner under any condition. It is suggested that accessibility of the social partner, rather than close physical proximity, has an important influence on the foraging squirrel monkey. © 1995 Wiley-Liss, Inc.

To explore behavioral patterns in bonnet macaque mother-infant dyads under environmental challenge, the motivation of infants to contact their mothers during a 1-hr foraging period was manipulated in two ways. First, sessions were given in which the infants were separated from their mothers for 3 hr prior to the foraging period. Second, sessions were given in which the infants were allowed access to food prior to the foraging period, thereby presumably reducing their motivation to separate from mother to seek food for themselves during the foraging period. Neither manipulation resulted in heightened conflict within the dyads. Separation of the infants prior to the foraging period did result, in general, in mothers forfeiting foraging task engagement to attend to their infants. The extent to which a mother exhibited this pattern correlated with her level of foraging effectiveness.

The purpose of this study was to determine the impact of infant restraint on dyadic interactions and maternal foraging patterns. Five bonnet macaque (Macaca radiata) mother-infant dyads were observed under three conditions: high foraging demand for the mothers with nonrestrained contact between mothers and infants (HFD-NRC), high foraging demand with restrained contact (HFD-RC), and low foraging demand with restrained contact (LFD-RC). In the restrained contact conditions the infants lived in a nursery within the group pen that allowed dyadic nursing, contact, proximity, and grooming, but prevented the infants from being with their mothers in the remaining portions of the pen, including the foraging area. Observations began when the infants were a mean of 5.4 months old. HFD-RC resulted in decreased dyadic contact relative to HFD-NRC, but did not significantly affect foraging task engagement; there were, however, marked individual differences in the response patterns of the mothers. Dyadic contact was also decreased during the LFD-RC condition, but maternal patterns under low demand resulted in lower levels of infant contact initiation. This study demonstrated the feasibility of a nursery-restrained rearing paradigm in exploring the strategic patterns of coping with conflicting environmental and maternal demands in bonnet macaque mothers. © 1993 Wiley-Liss, Inc.

Four groups of squirrel monkeys were observed to determine the primary basis of adult group structure. These studies included observations on (1) intact and gonadectomized males and females during and after breeding; (2) intact adults only; (3) subadults only; and, (4) a mixed group of adults and subadults. The spatial distribution of subjects in each group was used as a basic measure of social organization. It was found that for adults, regardless of hormonal status, between-sex distances were consistently greater than within-sex distances. This sexually segregated adult structure was largely attributable to the females' attaction to one another and overt rejection of the males. Subadults by themselves did not show any clear sexual segregation. However, in the presence of an adult structure, the subadults gradually manifested the segregated pattern of the adults by gravitating toward same-sex adults. These results indicate that the socialization process, rather than endogenous hormonal status, is the major determinant of adult social structure in squirrel monkeys.

A group of twelve bonnet macaques (Macaca radiata) raised in partial social isolation from birth to adulthood expressed moderate-to-severe behavioral disturbance as a function of their early rearing environments. The range of these behavioral function of their early rearing environments. The range of these behavioral abnormalities in this species are described for the first time. In order to assess the role of the current environment on their behavior, the animals as a group were required to obtain all of their food from a foraging device presenting two levels of difficulty. The therapeutic effect of the imposed foraging task was dependent upon the individual's status in the dominance hierarchy. Low- and high-ranking animals responded positively and became more social (338% above baseline levels) and showed lower levels of specific abnormal behaviors (nearly 75% lower). Mid-ranking animals responded negatively and became less social (89% lower), while their levels of abnormal behavior dramatically increased (200% higher).

The relationship between foraging demand and social behavior was experimentally studied in a laboratory group of bonnet macaques. Fourteen adult animals were housed in a large outdoor enclosure containing three shallow gravelfilled circular containers that served as the foraging sites. During the experimental foraging sessions raisins were placed in the containers and the social and foraging behaviors of the group were observed for 50 min following the distribution of raisins. Three types of foraging conditions were inter-spersed with one another on different test days: (1) surface load— raisins placed on top of the gravel; (2) buried load— raisins hidden underneath the gravel; and (3) sham load— no raisins placed at the foraging sites. Three basic foraging patterns, defined along a temporal dimension, were seen. One group of animals completed 50% of their total foraging by the end of the first 15 min. A second group foraged more steadily through the session. A third group foraged late, completing 50% of their foraging during the last half of the session. The foraging patterns were similar in the buried and surface condition, although the patterns were more compressed during the surface condition. More aggression and more avoidance of other animals occurred in the buried condition than in the surface condition. Very little foraging occurred during the sham condition. There was no clear relationship between the patterns of interaction during foraging and nonforaging observation sessions. The results suggest the value of manipulative laboratory studies in examining the relationship between ecological variables and social behavior in nonhuman primates.

Differential handling of male and female infants by their mothers and differential behavior of male and female infants independent of maternal behavior is a critical research issue with significant implications for understanding human development. This report describes mother-infant interaction in the squirrel monkey as a function of the infant's sex in a variety of laboratory environments. In a complex social environment, males move away from their mothers at a younger age than do females. The mothers then attempt to keep the males physically close. This maternal effort at continuing mother-son closeness is not successful, indicating greater infant-activated autonomy in the male.

The physiological and behavioral factors underlying the annual reproductive cycle of the squirrel monkey were evaluated under controlled laboratory conditions. Mating activity following the formation of two social groups served to synchronize the reproductive phases during the subsequent year of observation. Changes in male and female reproductive status were assessed during four designated phases: breeding, pregnancy, lactation and fatting. Behavioral and somatic changes in gonadectomized subjects, living in the social groups, were also evaluated. The variations in behavior and physiology across the year were considered in terms of factors constraining the timing of the natural reproductive pattern.

Diagnostic pregnancy assessments have been carried out in 18 squirrel monkey females using Delfs' method for chorionic gonadotropin bioassay palpatory, x-ray and other auxiliary techniques. Out of the 24 bioassay tests performed, 11 were positive (one of them weakly positive) and 13 negative. These results were confirmed by the other parallel measures, except in two cases of possible false positive reactions. No false negative results were noted. The implications of the results are discussed in terms of the sensitivity and reliability of the bioassay in the early diagnosis of pregnancy in the squirrel monkey.

During tests of sexual behavior which permitted multiple ejaculations, male bonnet and pigtail macaques were found to differ on a number of traditionally defined behavioral parameters. Although pigtail tests were terminated by a more stringent criterion, they were longer in duration and more ejaculations were recorded than in the bonnet tests. Pigtail males required relatively more intromissions for initial ejaculations and somewhat fewer on successive ejaculations. Bonnets, on the other hand, generally ejaculated on the first mount of a test and then exhibited increased numbers of intromissions to successive ejaculations. Although both species exhibited increases in successive postejaculatory intervals, the changes were more gradual for the pigtails.

Laboratory-born adolescent squirrel monkeys, drawn from four separate rearing groups, were placed together. Strong consistent preferences for interacting with others of the same rearing group were observed in 6 weeks of initial observation and persisted in follow-up observations 14 months later. Play was the major type of interaction between strangers and may serve as the primary mechanism through which social integration occurs.

Survival of the infant primate is a complex affair. It must meet the necessary metabolic demands for the support of its basic biology. But, in addition, its broad cognitive potential and the complexity of the social milieu into which it ultimately must move as an independent individual require the development of a rather immense array of selective behavioral responses. Unlike the survival of their more primitive phyletic antecedants and contemporaries, the survival of the infant primate to reproductive maturity reflects an intricate blend of genetic endowments and experiential formants in determining the range of stimuli, social and inanimate, that will be sought and approached, accommodated to or “ignored,” circumvented or actively avoided.

1 The Taxonomy and Distribution of Squirrel Monkeys (Saimiri).- 1. Introduction.- 2. Methodology.- 3. Methods.- 4. Results.- 4.1. Saimiri sciureus sciureus.- 4.2. Saimiri sciureus boliviensis.- 4.3. Saimiri sciureus cassiquiarensis.- 4.4. Saimiri sciureus oerstedii.- 4.5. Saimiri madeirae.- 5. Discussion.- Appendix 1. Taxonomic Borborygme.- Appendix 2. Specimens Examined.- References.- 2 The Behavior of Squirrel Monkeys (Saimiri) in Natural Environments.- 1. Introduction.- 2. Specializations.- 2.1. Diet.- 2.2. Locomotion.- 2.3. Habitat.- 3. Activity Pattern.- 4. Group Size.- 5. Home Range.- 6. Social Behavior and Organization.- 6.1. Mating Activities.- 6.2. Birth Season.- 6.3. After Birth Season.- 6.4. Juveniles.- 6.5. Sexual Maturation.- 6.6. Communication.- 7. Relations with Other Species.- References.- 3 Cognition in Squirrel Monkeys: A Contemporary Perspective.- 1. Introduction.- 2. Sensory, Motor, and Cognitive Attributes Underlying Behavior.- 2.1. Vision and Looking Behavior.- 2.2. Attention.- 2.3. Habituation and Sensitization.- 2.4. Memory.- 2.5. Response to Novelty (Curiosity).- 2.6. Tempo of Motor Activity.- 2.7. Vigor and Frequency of Motor Activity.- 2.8. Variability of Motor Activity.- 2.9. A Heuristic Approach to Interspecific Comparisons of Cognitive and Sensorimotor Attributes.- 3. Performance on Selected Laboratory Tasks.- 3.1. Discrimination and Discrimination-Reversal.- 3.2. Concept Learning.- 3.3. Problem-Solving.- 4. Expression of Cognitive and Sensorimotor Characteristics in Everyday Behavior.- 4.1. Use of Space.- 4.2. Feeding and Activity Patterns.- 4.3. Group Cohesion and Dispersion.- 5. Topics for Future Research.- 6. Conclusion.- References.- 4 Squirrel Monkey Communication.- 1. Introduction.- 2. Overview of the Vocal Repertoire.- 2.1. Previous Studies of the Squirrel Monkey Vocal Repertoire.- 2.2. Major Functional Classes of Vocalizations.- 2.3. Infant Vocalizations.- 3. Inherited and Experiential Influences on Squirrel Monkey Vocalization.- 3.1. Introduction.- 3.2. Inherited Characteristics of the Squirrel Monkey Isolation Call.- 4. Visual Displays.- 4.1. Introduction.- 4.2. Facial Expressions.- 5. Olfactory Communication.- 6. Conclusion.- References.- 5 Physiological Consequences of Maternal Separation and Loss in the Squirrel Monkey.- 1. Introduction.- 2. Normal Development and Basic Separation Procedures.- 3. Adrenal Responses to Maternal Separation.- 4. Effect of Environmental Conditions and Social Support.- 5. Effect of Repeated Separation Experiences.- 6. Importance of Adrenal Activation during Separation.- 7. Effect of Separation on the Immune System.- 8. Neurotransmitter Activity during Separation.- 9. General Considerations.- References.- 6 Effects of Surrogate-Rearing on the Infant Squirrel Monkey.- 1. Introduction.- 2. Responsiveness to the Surrogate.- 3. Responses to Separation and Novelty.- 4. Social Behavior.- 5. Atypical Behaviors.- 6. Summary of Comparisons with Macaques.- References.- 7 Reproductive Cyclicity and Breeding in the Squirrel Monkey.- 1. Introduction.- 2. The Reproductive Cycle.- 2.1. Cycle Length.- 2.2. Cycle Endocrinology.- 2.3. Seasonal Influences and Captivity Adaptation.- 3. Ovulation and Fertilization.- 3.1. Normal Follicular Morphology.- 3.2. Ovulation Induction.- 3.3. Fertilization.- 4. Captivity Breeding and Artificial Insemination.- 5. Pregnancy.- 5.1. Diagnosis.- 5.2. Gestation Length.- 5.3. Time of Implantation.- 5.4. Placental Physiology.- 5.5. Stillbirth and Abortion.- 6. Embryonic Development.- 7. Pregnancy Outcome.- 8. Summary.- References.- 8 The Endocrine System of the Squirrel Monkey.- 1. Introduction.- 2. Hormone Profile.- 3. Annual Reproductive Pattern.- 4. Diurnal Hormone Rhythm.- 5. Hormone Changes at Puberty.- 6. Effect of Body Weight.- 7. Hormone Differences in Saimiri Females.- 8. Psychological Influences on Hormone Secretion.- 9. General Considerations.- References.- 9 Thermoregulation in the Squirrel Monkey.- 1. Basic Concepts.- 2. Autonomic Thermoregulatory Responses.- 2.1. Method of Partitional Calorimetry.- 2.2. Stitt and Hardy's Experiment.- 2.3. Basic Data on Autonomic Thermoregulation.- 2.4. Probing Autonomic Capabilities with Thermodes.- 2.5. Autonomic Thermoregulation during Fever.- 2.6. Effects of CNS Lesions and Chemical Agents Other Than Pyrogens.- 2.7. Circadian Variations in Body Temperature.- 2.8. Autonomic Thermoregulation during Exposure to Microwave Fields.- 3. Behavioral Thermoregulation.- 3.1. Natural (Instinctive) Thermoregulatory Behaviors.- 3.2. Operant Control of the Thermal Environment.- 3.3. Probing Changes in Thermoregulatory Behavior with Thermodes.- 3.4. Important Parameters of Central Thermal Stimulation.- 3.5. Interaction between Behavioral and Autonomic Thermoregulatory Responses.- References.- 10 Sneezing Behavior in the Squirrel Monkey and Its Biological Significance.- 1. Introduction.- 2. Sneezing Behaviors: A Closer Look.- 3. On Functions and Effects.- 4. Sneezing Behaviors: What Function?.- 5. The Hypotheses on Trial.- 6. Sneezing: Functional Aspects.- 7. Epilogue.- References.- 11 Visual System of the Squirrel Monkey.- 1. Introduction.- 2. Organization of the Visual System.- 2.1. The Eye.- 2.2. Subcortical Visual Centers.- 2.3. Visual Cortex.- 3. Visual Capacities.- 3.1. Some Practical Issues.- 3.2. Visual Sensitivity.- 3.3. Color Vision.- 3.4. Spatial Vision.- 3.5. Binocular Vision.- References.- 12 Use of Squirrel Monkeys in Cardiovascular Research.- 1. Introduction.- 2. Naturally Occurring Atherosclerosis.- 2.1. Early Reports.- 2.2. Leticia, Colombia Study 1967.- 2.3. Squirrel Monkeys Compared to Other New World Monkeys.- 2.4. Histological Characteristics.- 3. Dietary Effects on Atherosclerosis.- 3.1. Summary of Lipid Changes.- 3.2. Composition of Diet.- 3.3. Type of Dietary Fat.- 3.4. Genetic Influences on Diet-Induced Atherosclerosis.- 4. Additional Effects on Diet-Induced Atherosclerosis.- 4.1. Effects of Age and Sex.- 4.2. Effects of Hypothyroidism, Insulin Deficiency, and Renally Induced Hypertension.- 4.3. Effects of Psychic Stress.- 5. Summary of Lesions and Complications of Atherosclerosis.- 5.1. Summary of Lesions by Location.- 5.2. Congestive Heart Failure.- 5.3. Myocardial Infarction.- 5.4. Aneurysms.- 5.5. Regression of Diet-Induced Atherosclerosis.- 6. Stress-Induced Cardiomyopathy.- 7. Behaviorally Induced Hypertension.- 8. Diseases Complicating the Use of Squirrel Monkeys in Cardiovascular Research.- 8.1. Cholelithiasis.- 8.2. Glomerulonephritis.- 8.3. Aortitis.- 8.4. Trypanosomiasis.- 9. Conclusion.- References.- 13 Behavioral Pharmacology of the Squirrel Monkey.- 1. Introduction: Procedures in Behavioral Pharmacology.- 1.1. Behavioral Pharmacology.- 1.2. Schedule-Controlled Behavior.- 1.3. Schedules Using Behavior Maintained by Food Presentation or Drug Injection.- 1.4. Schedules Using Noxious Stimuli.- 2. Determinants of the Behavioral Effects of Drugs.- 2.1. Response Rate.- 2.2. Behavioral and Pharmacological History.- 2.3. Nature of the Maintaining Event.- 2.4. Environmental Context.- 3. Behavioral Effects of Drugs in the Squirrel Monkey.- 3.1. Psychomotor Stimulants.- 3.2. Antianxiety Drugs, Sedative-Hypnotics, and Serotonin Antagonists.- 3.3. Antipsychotic Drugs.- 3.4. Opiates and Opiate Antagonists.- 3.5. Miscellaneous Compounds.- 4. Discriminative Stimulus Properties of Drugs.- 5. Drugs As Consequent Events.- 6. Drug Effects on Social Behavior.- 7. Comparison of Behavioral Effects of Drugs in the Squirrel Monkey with Other Species.- 8. Summary and Conclusions.- References.- 14 Nutrition and Metabolism of the Squirrel Monkey.- 1. Diet.- 1.1. Natural Habitat Diets.- 1.2. Diets Fed to Captive Animals.- 2. Requirements for Specific Nutrients.- 2.1. Introduction.- 2.2. Calorie Requirements.- 2.3. Protein Requirements.- 2.4. Fat Requirements.- 2.5. Carbohydrate Requirements.- 2.6. Mineral Requirements.- 2.7. Vitamin Requirements.- 2.8. Fiber.- 3. Growth and Body Composition As Affected by Diet.- 3.1. Infants.- 3.2. Adults.- 4. Nutritional and Metabolic Interactions.- 4.1. Introduction.- 4.2. Carbohydrate Metabolism: Glucose Tolerance.- 4.3. Protein Metabolism and PCM.- 4.4. Lipid and Lipoprotein Metabolism.- References.- 15 Immunology and Pathology of the Squirrel Monkey.- 1. Introduction.- 2. Simian Immunology.- 3. Agents of Disease.- 4. Infectious Agents, Immunological and Pathological Responses.- 4.1. Bacterial Infections.- 4.2. Fungal Infections.- 4.3. Parasitic Infections.- 4.4. Viral Infections.- 5. Comments and Perspectives.- References.- 16 Medical Care and Management of the Squirrel Monkey.- 1. Introduction.- 2. Colony Husbandry.- 2.1. Housing and Cage Requirements.- 2.2. Colony Records.- 3. Principles of Medical Management.- 3.1. Preventive Medicine.- 3.2. Therapeutic Approaches and Restraint.- 3.3. Methods of Treatment.- 4. Diseases of the Squirrel Monkey.- 4.1. Bacterial Diseases.- 4.2. Viral Infections.- 4.3. Parasitic Diseases.- 4.4. Deficiency Diseases.- 4.5. Other Diseases.- 5. Normative Data.- References.

Developmental weight gain was traced in two species of macaque, Macaca radiata and Macaca nemestrina. Some similarities in growth patterns between the two species were observed. Spontaneous obesity in bonnet macaques was observed, and growth curves of these specimens were compared with those of normal animals.

When Ernst Mayr (1961) declared that there are “two biologies,” a “How does it work?” and a “Why is it so?” biology, he stressed the division between two natural sciences: functional and evolutionary biology. Functional biologists study “proximate” causes—mostly physiological processes—and are not particularly concerned with the history or meaning of the genetic programs of the organisms that possess them. Evolutionary biologists, on the other hand, study “ultimate” causes—biological diversity and its meaning—and are much vexed by such questions as, “Why are there lions and tigers and things?” (Waddington, 1957). A familiar tale by the Brothers Grimm may illustrate the viewpoints of the two biologies. Little Red Riding Hood’s observation, “Grandma, What big teeth you have!,” exemplifies the view of a functional biologist; the Wolf’s reply, “The better to eat you with,” the point of an evolutionary biologist.

The nasal secretions expelled during sneezing in the squirrel monkey (Saimiri sciureus) were visualized under ultraviolet illumination. The quantity of nasal marking by six squirrel monkey groups in response to novel objects containing clean filter paper showed an ordinal decrement over a 3-day period. When one group was exposed to visually identical objects previously exposed to other groups, nasal marking to the olfactorily novel stimuli was highest on Day 1 and subsequently decreased over a 3-day exposure. Nasal marking in this species may reflect excitatory state and function in a type of olfactory communication previously undescribed for a primate species.