1,721,003 research outputs found
Female orgasm rate increases with male dominance in Japanese macaques
No full textUnder specific circumstances, nonhuman primate females may experience orgasm. The occurrence of female copulatory orgasm appears to be highly variable, however, and its proximate causation is poorly understood. We investigated the proximate mechanisms that control orgasmic response in female macaques. During 238 h of observation of sexual behaviour in a large captive group of Japanese macaques, Macaca fuscata, 240 copulations Were recorded involving 68 different heterosexual pairs formed by 16 males and 26 females. Female orgasmic responses were observed in 80 of 240 copulations (33%). The frequency of orgasms was not correlated with female age or dominance rank, but it was higher for copulations lasting longer and involving a higher number of mounts and pelvic thrusts. When the level of physical stimulation experienced by females during copulation was statistically controlled, the highest frequency of female orgasms was found among pairs formed by high-ranking males and low-ranking females and the lowest frequency among pairs formed by low-ranking males and high-ranking females. These findings suggest that the proximate mechanisms that control orgasmic threshold in female macaques are more responsive to social stimuli and less constrained by physiological limitations than previously thought. (C) 1998 The Association for the Study of Animal Behaviour
Analysis of tufted capuchin (Cebus apella) courtship and sexual behavior repertoire: Changes throughout the female cycle and female interindividual differences
No full text
Male aggressive harassment of consort pairs in a confined group of Japanese macaques.
No full textDisruption of rivals' mating activity is a prominent strategy for intrasexual
competition in many mammal species. In the present study, we analyzed
male aggressive harassment of consortships in a stable social group of
Japanese macaques (Macaca fuscata). The group was formed by 82
monkeys including 24 adult males and 32 adult females. A total of 238
hours of observation were made during the 1989-1990 mating season.
Data collection method was a combination of 'focal group" and 'complete
record" techniques.
A total of 57 episodes of aggressive harassment by males were recorded.
The intensity of harassment displayed by the aggressors ranged from stare
threat to physical attack. Higher-ranking males were responsible for
significantly more episodes of aggressive harassment than lower-ranking
males (t=2.1, df=14, p<.03). Even after excluding the dominant male, who
was responsible of 37 percent of all the episodes, the comparison
between the males of different rank yielded a significant difference (t=2.4,
df=13, p<.02). In most cases (68 percent of the total), the target of
aggressive harassment was the female partner of the consort pair. The
consort pairs with lower-ranking males did not receive more aggressions
than those with higher-ranking males (t=.62, df=67, ns). Similarly, the rank
of the female partner did not influence the frequency of male aggressive
harassment addressed to the consort pair (t=56, df=67, ns).
In order to have an indirect evaluation of the efficacy of aggressive
harassment in terms of intrasexual competition, we correlated the
frequency of aggressive harassment with various measures of male sexual
success. The number of episodes of aggression toward consortships
made by a male did not correlate with the number of his female mating
partners (rho=.17, ns), the number of different females with whom the male
was observed to ejaculate (rho=.22, ns), and the total number of
ejaculations (rho=.14, ns). These results, which are in keeping with
previous reports of male intrasexual competition in Old World monkeys,
make it difficult to interpret the functional significance of aggressive
harassment
Urine washing in tufted capuchins (Cebus apella): relationship with air temperature and relative humidity in indoor and outdoor conditions
No full textURINE WASHING IN TUFTED CAPUCHINS (CEBUS APELLA):
RELATIONSHIP WITH AIR TEMPERATURE AND RELATIVE
HUMIDITY IN INDOOR AND OUTDOOR CONDITIONS
Urine washing behavior has been observed in many platyrrhine monkeys and some
prosimians. Several functions have been attributed to it. In order to test a role of the
urine washing in the regulation of body temperature - by means of evaporative cooling -
the present study investigated the relationship between urine washing behavior and both
air temperature (T) and relative humidity (H) in tufted capuchins (Cebus apella). Group
scan sampling on five groups (N=43 animals) from 8 am to 6 pm provided 300 hours of
data. The varying outdoor (N=21 animals) versus the constant indoor condition (N=22)
allowed for the control of the T and H likely to influence a thermoregulatory response.
Results revealed a strong relationship between urine washing frequency and both T (posi-
tive correlation) and H (negative correlation) in the outdoor animals (p<.001), while no
correlation was found for indoor animals. Both outdoor and indoor urine washing fre-
quency showed a clear temporal pattern (p<.001) with a higher frequency around midday.
In addition, individual urine washing frequency per hour increased as the group size
increased. The presence of a temporal pattern during the day and the influence of the
social environment in affecting urine washing occurrence, support the hypothesis that
urine washing may have several functions over and above that of thermoregulatio
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