PubMed Health⌕ Search

Biomedical subjects

I S Bernstein

Publications and source records attributed to I S Bernstein.

At least 19 recordsLinked to original sources
PubMed1988

Activity patterns in a captive group of Celebes black apes (Macaca nigra).

Both time of day and weather significantly influenced the behavioral activity profile of a captive group of Celebes black apes. There were significant differences when their activity profile was compared to those of stumptail macaques, pigtail macaques, sooty mangabeys and geladas observed under similar conditions. There were, nonetheless several remarkable consistencies, especially among taxonomically related forms. Significant sex differences were also noted for grooming, social interaction rates, self-directed activity, agonistic and sexual behavior. Scores were consistent with data on a second group of black apes and previously reported unusual behavioral categories were confirmed.

Activity Cycles↗
PubMed1987

The evolution of nonhuman primate social behavior.

A review of the recent literature concerning evolutionary mechanisms and possible genetic contributions to social behavior reveals a concentration on function rather than mechanism. Although functional consequences may influence future genetic changes in a population, they do not necessarily reflect evolutionary history. More important, genes cannot code for functions. Only when the anatomical structures and behavioral patterns of individuals are described can we study genetic contributions to social organization. Discussions of function in the abstract, without specification of mechanism, do not fall within the realm of scientific testing.

Animals↗
PubMed1986

Selective interference in rhesus monkey (Macaca mulatta) intragroup agonistic episodes by age-sex class.

Adult male interference in agonistic episodes is strongly biased against adolescent and adult male participants, whereas adult female interference is biased in favor of kin and in support of younger animals against older animals. Although natal males also are biased in favor of their kin, their selective targeting of sexually mature males is independent of kinship. Adolescent males target adult males, but only in defense of kin. This selective interference against adolescent and adult males by adult males has the potential to profoundly modify male agonistic participation in intragroup encounters after puberty. Because female support is influenced primarily by kinship, females less consistently interfere against male agonistic participants. Adult males may therefore play an important role in the socialization of male agonistic expression.

Age Factors↗
PubMed1985

Age-sex differences in the expression of agonistic behavior in rhesus monkey (Macaca mulatta) groups.

Both age and sex influence rhesus monkey agonistic behavior. In intragroup episodes, submission was most frequent in juveniles, but aggression increased steadily with age, albeit much more sharply in females. As infants, males were more often involved in agonistic behavior than were females, but this sex difference reversed with age. A notable change in the frequency and forms of agonistic expression occurred in adolescent males. By the time they became adults, their participation in agonistic episodes was silent and brief and rarely involved biting. Adolescent males received high frequencies of aggressive responses, and this is hypothesized to account for the marked shift in adult male patterns of participation in intragroup agonistic interactions, as relative to females whose basic pattern of agonistic expression does not change with age.

Age Factors↗
PubMed1978

Changes in testosterone and behavior during adolescence in the male rhesus monkey.

Five adolescent male rhesus were followed for 3 years, from age 2 through age 4, with the collection of monthly testosterone levels, along with observation of behavior. Testosterone levels showed initial rises by age 3, but did not show the adult male seasonal pattern until 4. Play behavior fell significantly from age 2 to age 3, while sex behavior showed seasonal increases in both Year 2 and Year prior to the rise in plasma testosterone. The number of adult males in the social group may influence the timing of the rise in testosterone during adolescence. Injury may also serve to delay the increase in testosterone in males during their third year of development.

Age Factors↗
PubMed1978

Timing of births and reproductive success in rhesus monkey social groups.

Analysis of six years of birth records (228 potential reproductive years) from 71 female rhesus monkeys, housed in social groups in outdoor compounds, revealed several variables which influenced the reproductive pattern. The timing of conception in this seasonally breeding species was influenced by age, parity, and reproductive outcome the previous year, but not by social rank. In contrast, high social rank did confer an advantage in higher conception and lower infant mortality rates.

Age Factors↗
PubMed1978

Diurnal variation in plasma testosterone and cortisol in rhesus monkeys living in social groups.

Concentrations of cortisol and testosterone in the plasma of adult male rhesus monkeys living in social groups were determined during a 27-h period. Capture and venipuncture of experienced, conditioned animals did not lead to a fall in the concentration of testosterone in the plasma during the 90 min immediately after removal from the group. Both plasm cortisol and plasma testosterone concentrations showed a significant fall and rise in samples collected every 3 h during a 27-h period, even though there was considerable individual variation. During the autumn breeding season, animals showed higher concentrations of testosterone at both 10.00 and 22.00 h compared with those observed at the same times during the summer. Even though animals demonstrated significant diurnal changes, testosterone samples withdrawn at the same time of day (10.00 h) on consecutive days were significantly correlated with one another (r = 0.65, n = 27, P less than 0.01), suggesting the usefulness of sampling once a day to study potential environmental influences on plasma testosterone concentrations.

Animals↗
PubMed1977

Behavioural and hormonal responses of male rhesus monkeys introduced to females in the breeding and non-breeding seasons.

Six adult male rhesus monkeys were introduced individually to an all-female group for 10 days during the mating season. The initial aggressive responses of the females were rapidly replaced by positive social behaviour, and each male achieved alpha status and had access to social and sexual partners. A repetition of this paradigm in the non-breeding season produced significantly more female aggression, and no male attained high rank or engaged in sexual or other social behaviour. Male testosterone levels rose following introduction to the females in both seasons, but were significantly higher during the breeding season. Hormonal levels following removal from the females suggest a complex interplay between social, sexual and seasonal variables and recent social experiences. The differences in female social behaviour with newly introduced males, as a function of season, suggest an explanation for the seasonal limitation of male troop transfers.

Aggression↗
PubMed1977

Behavioral research in breeding colonies of Old World monkeys.

The existence of an active behavioral research program using animals in primate breeding colonies was considered to be not only a compatable multiple use of animals, but a way of materially improving the management and efficiency of the breeding colonies. In colonies of monkeys specifically established for behavioral research programs directed at the examination of social relationships, incidental breeding resulted in levels of reproductive success equivalent to or greater than that normally experienced in colonies devoted entirely to breeding. Behavioral research revealed patterns of seasonality, fostering, kidnapping, and infant care which would otherwise have escaped notice and which would significantly influence culling and management choices in a breeding colony. Many young males and certain low ranking adult males actively contributed to reproduction. Females born and reared in the colonies were the most productive, exceeding wild born or other introduced females in reproductive efficiency. Specific recommendations for establishing, expanding and culling of nonhuman primate breeding colonies were derived from the behavioral research.

Animals↗
PubMed1976

Activity patterns in a sooty mangabey group.

Diurnal, temperature and weather influences on the activity profiles of a sooty mangabey group were compared to similar data previously reported for geladas and pigtail monkeys. Distinct behavioral profiles for each group were obtained despite the near identity of living conditions. Mangabey patterns in captivity appeared very similar to those reported for mangabeys in the wild. Sexually dimorphic behavioral patterns were demonstrated as well as the independence of several social orders. Infant care by multiple females and by males was observed and the conservative nature of mangabey responses to novelty noted.

Agonistic Behavior↗