Reproductive cycles of the talapoin monkey (Miopithecus talapoin).

Reproductive cycles of female talapoins living in caged breeding groups were followed over 7 years, using visible changes of the perineum. Changes in the perineum during the extended adolescence of this species are described. There was a clearly defined breeding season, although its onset was not so abrupt as in the wild. During the summer months females show very small perineal swellings or none at all. Even during the breeding season all stages of the follicular phase of cycles are highly variable. Completed menstrual cycles are relatively rare since talapoins are highly fertile; they may be somewhat shorter than fertile cycles. Cyclical activity is modifiable by social stimuli, and it is suggested that differences in synchrony of breeding between wild and captive populations might be due both to indequate climate cues and to a lower level of social stimulation in captivity. The concept of the menstrual cycle had limited value in predicting reproductive activity in this highly fertile seasonal breeder.     

Mirror responses in a group of Miopithecus talapoin

Studies of non-human primate self-recognition in mirrors demonstrate variation both within and between species. This study applied a rigorous methodology that took into account habituation of subjects to the mirror as an object and to the experimental situation. The species observed in our study was Miopithecus talapoin, which has been little studied in the wild or in captivity. Although this species shows several interesting characteristics, including complex social organisation and a high encephalization index, the talapoin monkeys in the study did not pass the mark test; however, they showed a prerequisite for self-recognition, namely comparing their body parts to the image of these in the mirror.     

Behaviour of the Talapoin monkey (Miopithecus talapoin) studied in groups, in the laboratory

The behaviour of the Talapoin monkey has been studied both qualitatively and quantitatively by observing small captive groups kept in the laboratory. The behavioural repertoire is compared with that of other Old World Catarrhines. Talapoins show greater similarities to Cercopithecus monkeys than to Erythrocebus, Macaca, Papio or Cercocebus . However, there are differences in behaviour between talapoins and Cercopithecus monkeys, which lend additional support to the view that the former should be placed in the separate genus Miopithecus .     

Interlimb coordination and gait in the brown lemur (Lemur fulvus) and the talapoin monkey (Miopithecus talapoin)

Patterns of interlimb coordination based on telemetered electromyography of extensor muscles are described for the brown lemur (Lemur fulvus) and the talapoin monkey (Miopithecus talapoin) in order to address the issue of possible motor programs for quadrupedal stepping in primates. Differences in modal patterns of ipsilateral limb coupling (phase intervals) between walking and galloping indicate that gait-specific programs do exist in primates, especially for symmetrical gaits. These preferred patterns distinguish primates from most other mammals (e.g., the domestic cat), but do not rule out the possibility of subtle differences among primates in species-specific mechanisms of neural control. Variability about the preferred modes is better interpreted as an expression of the flexibility or facultative capabilities of the neural mechanisms controlling locomotion than as “errors” in the motor program.     

The menstrual cycle and its effect on behaviour in the Talapoin monkey (Miopithecus talapoin)

The menstrual cycles of 14 captive Talapoin monkeys ( Miopithecus talapoin ) were studied by making serial observations on the vaginal smears and sexual skin swellings for up to 15 months. Twelve of these females menstruated and the mean duration of their cycle was32–9 days (95% confidence limits 28.0-37.7). The corresponding value for the seven most regular females was 33.0 days (29.1-36.8). There were rhythmic changes in the vaginal smears and sexual skin during the menstrual cycle. Maximum cornification of the smears and maximum sexual skin swelling were observed at midcycle; the sexual skin deflated and the smear became less cornified during the luteal phase. The follicular phase—i.e. from menstruation to maximum skin swelling lasted 20.4 days with a wide distribution, in contrast to the mean duration of the luteal phase (13.7 days) which showed a pronounced peak at 14 days. The menstrual cycle of the talapoin thus resembles those of certain other Old World monkeys that exhibit perineal sexual skin swelling.
Sexual behaviour of the male and female was maximal near the female's midcycle and minimal during the luteal phase, with intermediate values in the follicular phase. The males were most aggressive towards other females of the group when one female was at midcycle; there were no consistent changes in aggression between the male and the female herself. The number of times one animal looks at another (a characteristic behaviour pattern in talapoins) was measured and occurred most often at midcycle, but other preliminary observations indicated a more pronounced correlation between this behaviour pattern and an animal's position in the hierarchy.     

Medroxyprogesterone acetate, aggression, and sexual behavior in male cynomolgus monkeys (Macaca fascicularis).

Medroxyprogesterone acetate (MPA) is used clinically to treat male sex offenders, but there are conflicting reports about its effects on aggression. To investigate these matters in a nonhuman primate, four intact male cynomolgus monkeys were studied in a testing paradigm that involved the presence of a caged, aggression-arousing stimulus male either immediately before or during a pair-test with an ovariectomized, untreated female partner. After two 4-week periods of pretreatment baseline, males received weekly injections of 40 mg MPA either alone (two 4-week treatment periods) or in combination with testosterone replacement with sc implants (one period) and additional daily injections of 2 mg testosterone propionate (two periods). MPA was then withdrawn while testosterone replacement continued (three periods). The testing paradigm was effective in maintaining aggression, especially male-male aggression, for many months. Male-male aggression increased with MPA treatment, and increased further with testosterone replacement, whereas male-female aggression tended to change in the opposite direction. As in earlier studies, MPA decreased both plasma testosterone and male sexual activity, but restoring plasma testosterone levels in treated males failed to restore their sexual activity. MPA therefore has behavioral effects that are not mediated primarily by its suppression of circulating androgens.     

The influence of androgenic and estrogenic hormones on sexual behavior in castrated adult male pigs

The objectives of these studies were to evaluate the influence of testosterone propionate (TP), estradiol cypionate (EC), dihydrotestosterone propionate (DHTP), EC + TP, EC + DHTP, and TP + DHTP on traits of masculine sexual behavior in castrated adult male pigs of different breeds. Masculine sexual behavior was restored and maintained by TP, whereas EC initially activated sexual behavior, including copulation and ejaculation, but was unable to sustain copulatory behavior for the 8- to 18-week periods that were evaluated. Treatment with DHTP was ineffective for stimulation of sexual behavior; thus, it is suggested that testosterone promotes some aspects of masculine sexual behavior in male pigs via aromatization to estrogen, but both androgen and estrogen are required for maintenance of the full complement of masculine sexual behavior traits.     

Menstrual cycle patterns of hormones and sexual behavior in gorillas

Oppositely sexed pairs of gorillas were tested behaviorally during the menstrual cycle to determine the relationship between hormone concentrations of the female and the frequency of sexual activity by the pair. Five females were tested individually during two cycles with each of two males, but serum samples for hormone assay were obtained from each female only during the first cycle of testing. There was no clear relationship between hormones and behavior for the single cycle in which the serum samples were obtained, with the exception that no copulations occurred after the early luteal phase, when progesterone was greater than 5 ng/ml. Normalized behavioral data from all four test cycles for all pairs suggested that female-solicited copulations were restricted primarily to the periovulatory period. Male sexual initiative (by one of the males) accounted for most copulations temporally dissociated from the periovulatory period. Normalized hormone data for all of the females suggested that (1) attractivity was associated with estradiol concentrations during the follicular phase, (2) proceptivity with estradiol and testosterone at midcycle, whereas (3) receptivity was not associated with hormone patterns or cycle phase. The data suggest that hormones are one of several variables that contribute to the regulation of sexual behavior in gorillas.     

Steroids and sexual behavior in castrated male rheusus monkeys.

Sexual behavior of long-term castrated rhesus males was not increased by administration of the hydroxylated metabolite of testosterone (T), 17 beta, 19-dihydroxy-5 alpha-androstan-3-one diacetate (19-OH-DHTA) at a dose of 1 mg/kg/day. Simultaneous administration of 19-OH-DHTA and estradiol benzoate (EB) also failed to increase the level of sexual performance, but daily injection (1 mg/kg/day) of testosterone propionate (TP) was very effective in effective in activating sexual behavior.     

Expression of adult female patterns of sexual behavior by male, female, and pseudohermaphroditic female rhesus monkeys

Gonadally intact pseudohermaphroditic female and normal female and neonatally castrated male rhesus monkeys were given estrogen treatment as adults and evaluated for attractivity, proceptivity, and receptivity during tests with a tethered stud male. Pseudohermaphrodites were produced by injecting their mothers during pregnancy with either testosterone propionate (TP) or dihydrotestosterone propionate (DHTP). Castrated males had reliably lower attractivity than normal females on all indicator responses shown by the tethered males. Additionally, castrated males showed reliably fewer proceptive responses on 4 of 5 measures than normal females. Receptivity could not be assessed in this situation for castrated males, because tethered males never contacted them unless the castrated males were displaying presentation. No reliable differences were observed between pseudohermaphrodites produced by prenatal treatments with TP or DHTP. Pseudohermaphrodites generally showed reliably less attractivity and proceptivity than normal females and reliably more of these traits than castrated males. Attractivity scores for pseudohermaphrodites were not different from those for normal females until proximity to the tethered male was established. Receptivity was not different in pseudohermaphrodites compared with normal females. Results indicate prenatal androgenization and its developmental sequelae lead to a defeminization in adulthood which, in this testing situation, was principally manifested by a deficiency in the performance of proceptive behaviors. Additionally, defeminization in rhesus monkeys, unlike that demonstrated in rodents, does not depend upon actions of an aromatizable androgen.     

Gonadal hormones modulate the display of submissive behavior in socially defeated female Syrian hamsters

There are striking differences in the behavioral response to social defeat between male and female Syrian hamsters. Whereas males exhibit a prolonged behavioral response to defeat (i.e., conditioned defeat), many females remain aggressive or show only a transient submissive response following defeat. The current study tested the hypothesis that sex steroids underlie this differential behavioral responsivity to social defeat. Female hamsters were ovariectomized and implanted with Silastic capsules containing estradiol (E(2)), testosterone (T), progesterone (P), dihydrotestosterone (DHT), or a blank capsule (no hormone replacement). After a 3-week recovery period, each subject was placed inside the home cage of a larger, more aggressive female for four 5-min defeat trials. The following day, each animal was tested for conditioned defeat by testing it in its own home cage in the presence of a smaller, non-aggressive intruder. Submissive, aggressive, social, and nonsocial behaviors were subsequently scored. Hamsters receiving E(2) or T displayed significantly lower levels of submissive behavior than did animals receiving P, DHT, or no hormone replacement. There were no significant differences in aggressive behavior among groups. These data suggest that gonadal hormones can influence submissive behavior in female hamsters. Collectively, these results suggest that the sex differences observed in conditioned defeat may, in part, be explained by sex differences in circulating gonadal hormones.     

Hormonal and social factors affecting evoked sexual behavior in Rhesus monkeys

Male rhesus monkey sexual behavior occurring spontaneously or evoked by remotely-controlled hypothalamic stimulation was studied in dominant and subdominant males with both dominant and subdominant, estrogen-treated or untreated, ovariectomized females. The behavior was quantified in terms of number and duration of ejaculatory sequences, number of thrusts, and number of mounts per sequence. Little or no spontaneous sexual behavior was observed with an untreated ovariectomized female. However, evoked sexual behavior with the exception of evoked ejaculation could be obtained whether the females were treated or untreated. Spontaneous and evoked sexual behavior was directed towards both dominant and subdominant females. The female chosen by the male was in part determined by the dominance status of the female. Evoked sexual behavior differed from spontaneous behavior in terms of an increased number of thrusts per mount, an increased number of ejaculations per session, and a decrease in latency between ejaculatory sequences.