ABSTRACT
From 1975 through 1991, three sets of twins were born from a total of 693 live and stillborn births (0.43%) at the UCLA/Sepulveda Veterans Administration Medical Center Nonhuman Primate Research Laboratory, CA. None of the twin's mothers were related. Positive patrilineal relationships have not been established; however, a brother (not a twin) of the first set of twins may have fathered the third set. All twins were born to multiparous females and, in each case, only one infant survived beyond 4 days. One set of twins was dizygotic; the genetic status of the others is unknown. © 1994 Wiley-Liss, Inc.
ABSTRACT
Personality ratings were completed in 97 socially living vervet monkeys (Cercopithecus aethiops sabaeus) ranging in age from 19 months to 14 years. Monkeys were rated on 17 distinct items on three separate occasions over a 14 month period. For each rating session, factor analysis resulted in similar factors: socially competent, playful/curious, and opportunistic, which are provisionally labeled as personality features. Individuals' scores on the three factors were linked to the subjects' social status, age, and sex. Relative to subordinate animals, dominant individuals had higher scores on the socially competent and lower scores on the opportunistic factors. Juvenile and subadult animals scored higher on playful/curious and opportunistic factors than adults. Females had higher scores on the opportunistic factor than males. Scores on the three factors changed during maturation, which suggests that some aspects of personality are age- and context-dependent. When group composition and social status were unaltered, intraindividual differences in factor scores were as consistent over time as were the rates of social grooming, being in proximity to others, resting, and other overt behaviors. Alterations in social status, group composition, and group membership were associated with changes in factor scores among some, but not all animals. These observations suggest that studies assessing personality can supplement ethological investigations of nonhuman primate behavior, and support the view that nonhuman Primates can serve as models for important features of human behavior. © 1994 Wiley-Liss, Inc.
ABSTRACT
The present study investigated a recently developed benzodiazepine, midazolam, as an intravenous adjuvant to ketamine in infant monkeys undergoing prolonged sedation during positron emission tomography of the brain and heart. Subjects were two rhesus macaque (Macaca mulatta) and ten vervet monkeys (Cercopithecus aethiops sabaeus) ranging in age from 26 to 260 days. Midazolam was an effective intravenous adjuvant to ketamine. This treatment regime resulted in complete immobilization of the animals. Ketamine infusion rates did not vary significantly with age for either species. Sensitivity to midazolam appeared to be age-dependent in vervets because significantly lower dose rates were sufficient to maintain anesthesia in older animals. For rhesus monkeys, midazolam dose rates decreased until approximately 4 months of age, and increased gradually thereafter. © 1993 Wiley-Liss, Inc.
ABSTRACT
Among nonhuman primates the composition of social groups influences the interactions of group members. We assessed the effects of acute changes in social composition on behavior among 15 adult male vervet monkeys (Cercopithecus aethiops sabaeus). Subjects were observed in their basal social groups which comprised 3 adult males, 2-4 adult females, and offspring; and in two subgroups consisting of either two or three adult males. Agonism and vigilance increased in smaller groups relative to basal conditions, while subjects in two-male groups displayed more aggression than those in three-male groups. These findings suggest that, among male vervet monkeys, acute disruption of stable social groups increases aggressive behavior, and that the amount of agonism is influenced by the composition of the consequent subgroups. © 1992 Wiley-Liss, Inc.
