Effect of stress-inducing factors on the behavior of monkeys. I. The behavior of monkeys under acute emotional stress

The behavior of Papio hamadryas pubertal males under the immobilizational stress conditions has been studied. It has been established that this very type of stress appeared to be a powerful irritant for the individuals of this species and age leading them into the depression state. The process of normalization of behavior after the 2-hour immobilization lasted for about 72 h. The main consequences of the stress were the violation of locomotion, the reception by individuals of unnatural postures, the trembling of limbs and the violation of coordination. The reaction of stress was greatly influenced by the position of individual in the hierarchic system. The dominant (alpha) and the most subdominant (z) males bore the stress easier. The intensification of food activity was marked within the male z. In certain period after the immobilization the tendency of the growth of friendly contacts between the individuals was found. The frequency of aggressive behavior after the stress lowered. The violation of manipulation activity was also marked. These regularities are of great importance for the reconstruction of group social behavior models of protohominid's societies.     

Hormonal activity of the hypophysis-gonadal system in male hamadryas baboons in relationship to their hierarchical position

Hierarchic status-dependent hormonal activity of pituitary-gonadal system was studied in an isolated group of hamadryas baboons. Testosterone level was higher in dominating males. The level of sex hormone was higher in aged animals with great muscle mass. No correlation was observed between hierarchic status of hamadryas baboon males and the blood level of luteinizing hormone.     

Effect of immobilization stress on the gonadotropic function of the hypophysis in male hamadryas baboons (Papio hamadryas)

The plasma levels of luteinizing hormone (LH) and testosterone were studied in intact and castrated male baboons exposed to 2- and 10-hour periods of immobilization. Presented data have shown that immobilization stress induced a marked decrease in LH concentration both in intact and castrated monkeys. Changes in LH concentration positively correlated with plasma levels of testosterone only during the experimental procedures. During three days after immobilization there was a sharp dissociation in the dynamics of testosterone levels remained low and LH returned to normal values. We can suggest that it is not absolute LH level that is responsible for the changes in testosterone secretion during the immobilization stress.     

Acclimatization of hamadryas baboons on the Black Sea coast of the Caucasus: their territorial behavior

The territorial behaviour of hamadryas baboon troop was studied from November 1984 up to February 1986. The observations were carried out from the time of animals' awakening till their arrangement for a night sleep using the method of daily tracking with recording to behavioural action frequency for all visible animals with definite intervals. It has been established that the size of habitat ranges depends on food resources. The travels across the territory has a seasonal nature.     

Effect of ACTH on the corticosteroid and progesterone levels in female hamadryas baboons in relation to the menstrual cycle phase

The effect of exogenous ACTH on the endogenous function of the steroid-producing glands has been investigated in hamadryas baboon females depending on the level of sex hormones in the body. The content of corticosteroids and progesterone in peripheral blood plasma was measured by radioimmunoassay. It has been established that the time course of changes in the adrenal gland response to administration of a standard ACTH dose was of the same type in the different menstrual cycle phases. The inhibitory effect of ACTH on progesterone secretion in ovarian corpus luteum being active has been revealed.     

Allogrooming and social status: An assessment of the contributions of female behavior to the social organization of hamadryas baboons (Papio hamadryas)

Three isosexual social groups, each containing ten subadult female hamadryas monkeys (Papio hamadryas) were studied for seven months to test three hypotheses dealing with the assumptions underlyingSeyfarth's (1977) model of allogrooming and social organization. Aggression, avoid and allogrooming behaviors were used as criteria for studying the social organization of the groups. UsingLandau's (1951) index and discriminant analyses, we found that each of the three isosexual female social units conformed to a model of social organization having a non-linear hierarchy and only two major strata: a dominant animal and subordinates who were largely undifferentiated. This aspect of social organization is similar to the normal one-male unit leader harem form of social organization that is typical of hamadryas. However, since no male was present, the role of unit leader was filled by a female. The length of allogrooming bouts and the amount of allogroom received was affected by the social status of the recipient, with high status individuals receiving more than low status individuals. Social peers were not observed competing for access to high status individuals and did not exchange most of their grooming among themselves. We found that the assumptions underlyingSeyfarth's (1977) model were not appropriate for the type of social organization typically found in hamadryas monkeys, thus suggesting the need for further modification of the model so that it fits available data.     

Functional activity of the adrenal system in relation to the hierarchical status of male hamadryas baboons in an isolated group

The correlation between hormonal activity of hypophysis-gonad system and hierarchical status of hamadryas baboon males in an isolated group was studied. It has been established that the level of testosterone was higher in males occupying the leading position in a separate subgroup. A high level of sexual hormone was observed in animals with greater muscular mass and age. No correlation between hierarchical status and luteinizing hormone blood content has been observed in baboon males.     

Sexual dimorphism in two subspecies of Ethiopian baboons (Papio hamadryas) and their hybrids

Sexual dimorphism in mammals has been related to such variables as absolute body size, ecology, and various aspects of social behaviour. Attempts to relate dimorphism to any of these variables have necessarily used small heterogeneous samples to represent the relevant species. We are concerned by the inevitable exclusion of any measure of variability in dimorphism and the consequent impossiblity of assessing the significance of observed interspecific differences. In this paper we describe aspects of sexual dimorphism in anubis,hamadryas, and hybrid baboons from Ethiopia. Samples are large enough to permit a measure of intrapopulation variability. Hamadryas baboons are more dimorphic than anubis in epigamic features, but not in postcanine dentition, nor, contrary to previous reports, in body weight or canine tooth size. Hybrid males are more hamadryas-like and hybrid females more anubis-like, as would be predicted by the proposed mechanism for the establishment of the hybrid zone, namely the capture of anubis females by hamadryas males.     

The relationship of accentuated lines in enamel to weaning stress in juvenile baboons (Papio hamadryas anubis)

Weaning conflict may represent an evolutionary conflict of interest between parent and offspring, an honest signal of need on the part of a weanling, or both. Accentuated lines visible in histological sections of teeth are indicators of stress during enamel formation and have been hypothesised to form in baboon teeth during weaning. We analysed growth increments in 5 tooth sections from 2 Ugandan baboons (Papio hamadryas anubis), using polarised light microscopy, to determine when stresses occurred during the weaning process. Dietary transitions were reconstructed using normalised strontium intensities (Sr/Ca) in enamel. Accentuated lines were cross-matched between teeth from the same animal and plotted by month. The highest frequency of stress was experienced at around 6 months in 1 baboon, coinciding with an inferred reduction in suckling frequency, and at 11 months in another, coinciding with the inferred cessation of suckling. Because accentuated lines appear to indicate weaning stress at dietary transitions, weaning conflict may represent an honest signal of need on the part of the weanling.     

Effects of chronic melengestrol acetate contraceptive treatment on perineal tumescence,body weight,and sociosexual behavior of hamadryas baboons (Papio hamadryas)

Melengestrol acetate (MGA) subcutaneous implants were used in seven adult female Hamadryas baboons to study the effects of chronic progestin administration on perineal swelling, behavior, and weight gain. At the dose level used (≥8 mg/kg body weight), cycles of perineal tumescence ceased and swellings subsided. Social dynamics were not significantly altered during treatment, and only minor changes in agonistic interactions were noted following implant removal. Body weight increased by 17.3–47.6% during treatment despite decreased time spent foraging. This paradox may be explained by 1) foraging time not necessarily corresponding to total intake and 2) the nonsignificant trend toward lower levels of activity during treatment. Treatment with MGA can be recommended based on its ability to suppress ovarian cyclicity without causing social disruption. However, because this and other progestins stimulate weight gain, their use is contraindicated in overweight or obese animals. © 1995 Wiley-Liss, Inc.     

Hormonal correlates of changes in interest in unrelated infants across the peripartum period in female baboons (Papio hamadryas anubis sp.)

In past research on human and nonhuman primates, maternal responsiveness and behavior has been thought of as an experiential, cognitive mechanism; however, recent findings have shown that maternal motivation and behavior may not be entirely divorced from the endocrine system. To investigate the relationship between interest in infants and the hormonal changes related to pregnancy, we examined the nature of social interactions across parturition between a large sample (n = 133) of adult female baboons (Papio hamadryas anubis sp.) and unrelated infants. Prepartum data were collected during ten 30-min focal observations for each subject. Each mother-infant pair was then observed through the infant's first 8 weeks of life. A total of 2325 h of observation was recorded. Urine was collected on 65 subjects, starting 5 weeks before the expected date of parturition and ending 4 weeks after parturition. Evidence for a connection between endocrine function and responsiveness toward infants was found. Affiliative behaviors during the prepartum period were positively correlated to the estrogen/cortisol ratio and high dominance rank. In the postpartum period, affiliative behaviors were positively correlated with prepartum progesterone and dominance rank, and negatively correlated with postpartum cortisol levels. Finally, a positive correlation was recorded during the postpartum period between prepartum progesterone and aggression, and a negative correlation between postpartum cortisol and aggression and submission. Our data suggest that the endocrine changes that may help regulate maternal care of offspring also influence the way in which pre- and postpartum female baboons interact with unrelated infants in their social group.     

Greeting movements among adult males in a colony of baboons:Papio hamadryas,P. cynocephalus and their hybrids

Seven greeting movements performed by four adult males belonging to a colony of baboons (Papio hamadryas, P. cynocephalus and their hybrids) were described. The hamadryas male has more number and more refined repertoire of movements than the yellow baboons, what would mean that the greeting movements possess a species-specific nature. This characteristic is expressed also by the existence of some inappropriate responses of the yellow baboons to the greeting of the hamadryas male. The differences in the greeting movements between both species would be explained as characteristic consequences of their social system organization. The hybrid male, having acquired a system organization similar to that of the hamadryas male, has acquired the same signal code, too, according to this system. The hybridization tendency would be adaptive in those colonies or troops with mixed species.     

Characteristics of specific adaptation to cold and their relation to aggressive behavior and the stress level in house mice

Change of calorigenic effect of noradrenaline after 5 week cold exposition (at 6-8 degrees C) as a criteria of specific adaptation was used. Individual differences of calorigenic reaction after cold exposition were negative correlation with blood corticosterone and positive correlation with aggressiveness in dyadic test.     

Effect of moisture stress on the growth ofPinus ponderosa Dougl. ex. Laws seedlings in relation to their field performance

Forty wind-pollinated families from eight provenances, four from xeric and four from mesic site types in the Sierra Nevada of California, were examined in the greenhouse for differential response to soil moisture stress. Analysis was made of shoot-root allometric growth coefficients, absolute and relative growth rates and the relationship among these response measures and growth in three field plantations. The results showed significant differences among families for allometric growth (k) coefficients under moderate stress, but no differences among provenances or between site types. Absolute and relative growth rate differences between site types were not significant under any treatment; however provenance differences were observed. Correlation coefficients between plantation performance and greenhouse growth estimates were sometimes significant but significance was plantation and treatment specific. Research performed while author was on sabbatical leave at the Institute of Forest Genetics, USDA-USFS, Placerville, California.     

Hormonal indices of the normal dolphin Turpsiops truncatus and in the dynamics of experimental stress

Radioimmune assay has been made of the content of cortisol, insulin, triiodothyronine (T3) and thyroxine (T4) in the blood serum of the dolphin under normal conditions and during 3- ad 6-hour stress. Normal levels of these hormones were found to be equal to 90.34 +/- 6.86 nmol/l, for cortisol, 64.1 +/- 11.1 pmol/l for insulin, 1.27 +/- 0.04 nmol/l for T3 and 138.3 +/- 8.9 nmol/l for T4. Seasonal changes in cortisol level were observed, hormonal concentration being significantly higher during winter and spring as compared to that during summer and autumn. On the whole, the dynamics of hormonal shifts during stress reaction in the dolphin is similar to that in the terrestrial animals reflecting the development of general adaptive syndrome.     

Effect of stressor factors on the behavior of monkeys. III. The behavior of rhesus macaques during immobilization stress

The three-hour immobilizational stress in two groups of males of rhesus monkeys at the age of 7-8 and 10-12 years has been investigated. The reaction on the stress has been established to depend on the age of animals. The young males bear the stress easier, their behaviour after it is practically normal. The normal behaviour of the elder animals restores during 24 hours after immobilization. A comparative analysis of hamadryas baboons and rhesus monkeys behaviour during this type of stress has been carried out. These species differ by their reaction on stress: Papio hamadryas serve as a model of hard depressive stress, the rhesus monkeys--a model of slight-stimulative stress. The peculiarities of stress bearing depend on the selected species, age of the animal, the type of social organization and individual features of behaviour.     

The prediction of resistance to emotional stress based on the individual testing of behavior

On the basis of the elaborated experimental model for testing of emotional interaction of animals individual typification of behaviour was established according to which all experimental male rats of August line were subdivided into groups: I--rats manifesting behaviour of avoidance, "victims" of electrocutaneous stimulation; II--without definite behaviour with respect to the "victim" rat; III--rats, preferring the behaviour determining electrocutaneous stimulation of the "victim" rat. All typified animals were subjected to emotional stress with the use of the elaborated experimental model of aggressive-conflict behaviour. Stability against emotional stress of each group of animals was studied. Significant differences were established of stability degree to emotional stress of the rats of three groups manifesting different types of behavioural reaction in conditions of emotional interaction. The most stable were rats of the I group, the least--of the III group; rats of the II group were in the middle position. Typification on the basis of testing of emotional interaction of animals allows to prognosticate individual stability against emotional stress.     

Fine structure of the parathyroid glands in baboons, Papio hamadryas in response to experimental hypercorticoidism

Female baboons maintained under laboratory conditions were subjected to a series of 10 weekly injections (4 mg/kg body weight) of the synthetic glucocorticoid, triamcinolone hexacetonide. In response to the treatment, serum immunoreactive parathyroid hormone (PTH) levels were raised, though blood calcium levels remained within normal physiological limits. Light and electron-microscopic studies were made on the parathyroid glands at the end of the experimental period. The baboon parathyroid glands were composed of 'light' and 'dark' forms of the chief cells in varying ratios from gland to gland even within a single animal. Glucocorticoid-induced parathyroid hyperactivity as measured by circulating PTH levels was not accompanied by cellular hypertrophy, though there was an increase in the relative number of 'light' cells. At the ultrastructural level, after treatment, many of the 'light' cells were found to contain more free ribosomes, larger profiles of granular endoplasmic reticulum and had better developed mitochondria. Interdigitations between adjacent chief cells were more complex in treated glands. Apart from these features, chief cells of treated glands were basically similar to those of untreated controls. Our study showed that functional parathyroid hyperactivity in baboons is not necessarily accompanied by significant ultrastructural changes in chief cells.