Fetal and maternal factors associated with infant mortality in vervet monkeys.

BACKGROUND: Causes of infant death remain unknown in significant proportions of human and non-human primate pregnancies. METHODS: A closed breeding colony with high rates of infant mortality had pregnancies assessed (n=153) by fetal measurements and maternal characteristics. Infant outcome was classified as neonatal death (stillborn or died <48 hours from birth), postnatal death (died 2-30 days) or surviving (alive after 30 days). RESULTS: Fetal size did not predict outcome. Poor maternal glycemic control and low social ranking increased odds for adverse outcome (OR=3.72, P=0.01 and 2.27, P=0.04, respectively). Male sex was over-represented in stillbirths (P=0.04), and many were macrosomic, but size did not associate with maternal glycemic control measured as glycated hemoglobin A1c. Postnatally dead infants were smaller (P<0.01), which associated with behavioral factors and glycemic control. CONCLUSIONS: Fetal growth estimates predicted gestational age but not fetal outcome. Maternal social status and metabolic health, particularly glycemic control, increased risks of adverse pregnancy outcome.

Biobehavioural correlates of hand preference in free-ranging female primates.

In this research we examined biological and behavioural correlates of handedness in a subject cohort of 41 free-ranging young female rhesus macaques (Macaca mulatta). Specifically, we examined relationships between handedness and cerebrospinal fluid (CSF) concentrations of the monoamine metabolites 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA), plasma concentrations of the hormones cortisol and adrenocorticotropin (ACTH), prolactin, and multiple indices of social behaviour, including proximity to other animals, grooming, submission, and aggression. Handedness was determined through systematic observation of animals reaching for food in their unrestricted home environment. We found a population-level bias for left-hand use in this cohort of young females. The frequency of right versus left hand use was positively correlated with CSF 5-HIAA, plasma cortisol concentrations, the frequency of submissive behaviour, and with the frequency of bouts in which animals received low-level aggression. The positive correlation between right versus left hand use, submissive behaviour, and received aggression found here in females contrasts with the negative correlation among these same variables that we have previously reported in rhesus males. We conclude that these results may be explicable in terms of sex-based differences in rhesus life-history patterns, and that the influence of the serotonergic system on patterns of male aggression, social behaviour, and handedness, and the associations between handedness and social behaviour found previously among males may not be generalised to female rhesus macaques.

Left-handedness is correlated with CSF monoamine metabolite and plasma cortisol concentrations, and with impaired sociality, in free-ranging adult male rhesus macaques (Macaca mulatta).

In this research we examined biological and behavioural correlates of handedness in free-ranging adult male rhesus macaques (Macaca mulatta). Specifically, we examined relationships between handedness and cerebrospinal fluid (CSF) concentrations of the monoamine metabolites 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), and 3-methoxy-4-hydroxyphenylglycol (MHPG), plasma concentrations of the hormones cortisol and adrenocorticotropin (ACTH), and multiple indices of social behaviour, including occurrences of proximity to other animals, grooming, submission, and aggression. We determined handedness through systematic observation of animals reaching for food in their unrestricted home environment. The frequency of right- versus left-hand use was significantly positively correlated with CSF 5-HIAA, CSF MHPG, and plasma cortisol concentrations, and with social proximity and the frequency and duration of bouts in which animals received grooming. The frequency of right- versus left-hand use was significantly negatively correlated with the frequency of submissive behaviour, and with the frequency and intensity of bouts in which animals received aggression. We conclude that handedness is associated with an array of biological and behavioural processes in free-ranging adult male rhesus macaques and that left-handedness may be used to identify individuals at increased risk for impaired functioning of the serotonin, norepinephrine, and hypothalamic-pituitary-adrenal systems, and for social isolation and susceptibility to violent attack.

Hormonal correlates of hand preference in free-ranging primates.

In this research we examined hormonal correlates of hand preference in free-ranging primates. Specifically, we tested the hypothesis that levels of the stress hormone cortisol and the male sex hormone testosterone are correlated with handedness in male rhesus macaques (Macaca mulatta). We found significant positive relationships between cortisol and testosterone levels sampled during adolescence and the frequency of right- versus left-hand use sampled during adulthood. These data indicate that adolescent measures of cortisol and testosterone are correlated with hemispheric specialization in adult free-ranging primates.

Token-mediated tool-use by a tufted capuchin monkey (Cebus apella).

This research examined token-mediated tool-use in a tufted capuchin monkey (Cebus apella). We conducted five experiments. In experiment 1 we examined the use of plastic color-coded chips to request food, and in experiments 2-5 we examined the use of color-coded chips to request tools. Our subject learned to use chips to request tools following the same general pattern seen in great apes performing analogous tasks, that is, initial discrimination followed by an understanding of the relationship among tokens, tools, and their functions. Our findings are consistent with the view that parallel representational processes underlie the tool-related behavior of capuchins and great apes.