Evidence of a limited role for prolactin in the preparturient activity of confined gilts

To investigate the role of peripheral prolactin in stimulating the preparturient activity of pigs, 12 cross-bred gilts housed in standard farrowing crates either received orally 10mg of bromocriptine three times per day from day 110 of gestation or served as controls. Jugular blood samples were collected on days 107 and 113 and assayed for prolactin, while the gilts' behaviour was recorded during the last 24h before parturition. Bromocriptine eliminated the preparturient rise in prolactin concentrations (P=0.002). As parturition approached all gilts initially spent less time laying down and more time standing or sitting. The frequency of posture changes also increased as did the incidence of oro-nasal behaviours. These trends were reversed during the final 5-8h before parturition, when the gilts began to lay down for longer periods. The mean concentrations of prolactin on day 113 were correlated with the frequency of posture changes (r=0.70,P=0.015) but not with any other behavioural measure (P>0.10). Bromocriptine had no overall effect on any of the preparturient behaviours (P>0.10) but did reduce the frequency of posture changes 13-16h before parturition (P=0.05). There was a significant interaction between time until parturition and bromocriptine treatment for time spent lying down (P=0.013): bromocriptine delayed the time when the gilts began lying down again as parturition approached. The results suggest that peripheral prolactin plays only a limited role in the preparturient activity of pigs and throws some doubt on its importance in the motivation of nest building in this species.     

Positional behavior and substrate use in wild adult bearded capuchin monkeys (Sapajus libidinosus)

Natural selection for positional behavior (posture and locomotion) has at least partially driven the evolution of anatomical form and function in the order Primates. Examination of bipedal behaviors associated with daily activity patterns, foraging, and terrestrial habitat use in nonhuman primates, particularly those that adopt bipedal postures and use bipedal locomotion, allows us to refine hypotheses concerning the evolution of bipedalism in humans. This study describes the positional behavior of wild bearded capuchins (Sapajus libidinosus), a species that is known for its use of terrestrial substrates and its habitual use of stones as tools. Here, we test the association of terrestrial substrate use with bipedal posture and locomotion, and the influence of sex (which co‐varies with body mass in adults of this species) on positional behavior and substrate use. Behavior and location of 16 wild adult bearded capuchins from two groups were sampled systematically at 15 s intervals for 2 min periods for 1 year (10,244 samples). Despite their different body masses, adult males (average 3.5 kg) and females (average 2.1 kg) in this study did not differ substantially in their positional behaviors, postures, or use of substrates for particular activities. The monkeys used terrestrial substrates in 27% of samples. Bipedal postures and behaviors, while not a prominent feature of their behavior, occurred in different forms on the two substrates. The monkeys crouched bipedally in trees, but did not use other bipedal postures in trees. While on terrestrial substrates, they also crouched bipedally but occasionally stood upright and moved bipedally with orthograde posture. Bearded capuchin monkeys' behavior supports the suggestion from anatomical analysis that S. libidinosus is morphologically better adapted than its congeners to adopt orthograde postures.     

Association of physical activity intensity and bout length with mortality: An observational study of 79,503 UK Biobank participants

BackgroundSpending more time active (and less sedentary) is associated with health benefits such as improved cardiovascular health and lower risk of all-cause mortality. It is unclear whether these associations differ depending on whether time spent sedentary or in moderate-vigorous physical activity (MVPA) is accumulated in long or short bouts. In this study, we used a novel method that accounts for substitution (i.e., more time in MVPA means less time sleeping, in light activity or sedentary) to examine whether length of sedentary and MVPA bouts associates with all-cause mortality.Methods and findingsWe used data on 79,503 adult participants from the population-based UK Biobank cohort, which recruited participants between 2006 and 2010 (mean age at accelerometer wear 62.1 years [SD = 7.9], 54.5% women; mean length of follow-up 5.1 years [SD = 0.73]). We derived (1) the total time participants spent in activity categories—sleep, sedentary, light activity, and MVPA—on average per day; (2) time spent in sedentary bouts of short (1 to 15 minutes), medium (16 to 40 minutes), and long (41+ minutes) duration; and (3) MVPA bouts of very short (1 to 9 minutes), short (10 to 15 minutes), medium (16 to 40 minutes), and long (41+ minutes) duration. We used Cox proportion hazards regression to estimate the association of spending 10 minutes more average daily time in one activity or bout length category, coupled with 10 minutes less time in another, with all-cause mortality. Those spending more time in MVPA had lower mortality risk, irrespective of whether this replaced time spent sleeping, sedentary, or in light activity, and these associations were of similar magnitude (e.g., hazard ratio [HR] 0.96 [95% CI: 0.94, 0.97; P < 0.001] per 10 minutes more MVPA, coupled with 10 minutes less light activity per day). Those spending more time sedentary had higher mortality risk if this replaced light activity (HR 1.02 [95% CI: 1.01, 1.02; P < 0.001] per 10 minutes more sedentary time, with 10 minutes less light activity per day) and an even higher risk if this replaced MVPA (HR 1.06 [95% CI: 1.05, 1.08; P < 0.001] per 10 minutes more sedentary time, with 10 minutes less MVPA per day). We found little evidence that mortality risk differed depending on the length of sedentary or MVPA bouts. Key limitations of our study are potential residual confounding, the limited length of follow-up, and use of a select sample of the United Kingdom population.ConclusionsWe have shown that time spent in MVPA was associated with lower mortality, irrespective of whether it replaced time spent sleeping, sedentary, or in light activity. Time spent sedentary was associated with higher mortality risk, particularly if it replaced MVPA. This emphasises the specific importance of MVPA. Our findings suggest that the impact of MVPA does not differ depending on whether it is obtained from several short bouts or fewer longer bouts, supporting the recent removal of the requirement that MVPA should be accumulated in bouts of 10 minutes or more from the UK and the United States policy. Further studies are needed to investigate causality and explore health outcomes beyond mortality.

Louise Millard and co-workers study associations between bouts of moderate-to-vigorous physical activity and mortality.     

抱崽与否对笼养雌性食蟹猴个体社会行为的影响

目的比较笼养雌性食蟹猴抱崽与否,是否对其社会行为有影响。方法从2010年5月开始,在江苏省苏州中科实验动物有限公司猴场可观察的个体中,随机抽取观察对象40个;同年10月开始正式拍摄,样本中,11个个体抱崽,29个个体未抱崽。三名观察员采用焦点观察法,使用高清摄像机,对所有个体每天跟踪拍摄7个时间片段,每个时间段为30分组,每个个体观察4 d,共计完成有效累积观察时间560 h;将每天所拍摄视频汇总而后随机分配给NOLDUS分析员分析转换成为行为数据。结果抱崽个体多数时间是怀抱住幼崽,社会友好行为较多,比如为其他个体理毛或被其他个体理毛;社会地位较高,如与猴王共坐于制高点(悬于空中的板子或链子上,依据各个猴场饲养条件而议)时间较长;通讯行为较多,即努嘴行为;运动行为和交配行为较多;而未抱崽个体聚温行为较多,即与其他个体相互怀抱聚温;两组在摄食行为、发情行为、休息行为、冲突行为、警戒行为和各种自我行为差异无显著性。结论抱崽对雌性食蟹猴的社会行为有影响。     

Actividades diarias evaluadas mediante monitor de actividad de alta precisión en adultos mayores: resultados preliminares del Estudio IMPACT65+

Introduction

Physical activity and physical inactivity patterns can affect health status. In the elderly people, their study is relevant given the importance that they have on the morbidity and mortality.

Positional behavior,selective use of habitat substrate and associated non-positional behavior in free-rangingColobus guereza (Rüppel, 1835)

Positional behavior (posture and locomotion), associated social/maintenance behaviors and selective utilization of available habitat structure were recorded for free-rangingColobus guereza occupying a remant montane forest near Limuru, Kenya. This research design focuses on relationships between anatomy, behavior, and the environment and provides a framework for interpreting adaptations inColobus. Quantitative analyses show daily activity patterns. These monkeys spend most of their time in above branch postural activities, primarily in sitting postures. Locomotion accounts for less than one-fifth of positional behavior. In both postural and locomotor sequences, the forelimbs may be placed above the shoulder complex, often in abducted positions. Suspensory positional behavior is rare. Most activity occurs within Zone II, flexible branches of medium diameter and less than 45° in grade. Selective use of the substrate and preferred positional modes are related to variables such as social/maintenance activities, weight distribution of the link system and substrate configuration. These data suggest that, (a) black and white colobus do not exhibit behavior associated with so-called “semibrachiation” and (b) bio-behavioral adaptations involving foraging and feeding strategies may account, in part, for observed morphological differences among Old World monkeys.     

Social play behavior in infant Sichuan snub-nosed monkeys (Rhinopithecus roxellana) in Qinling Mountains, China

We describe the development of social play behavior and assess factors influencing the development of play in infant Sichuan snub-nosed monkeys (Rhinopithecus roxellana). Infant snub-nosed monkeys began to exhibit social play at 3 months of age, when they spent an average 0.89% of time engaging in this behavior (range: 0.7-1.12%). At 6 months of age, there was a significant increase in the proportion of time spent in social play, averaging 9.78% of observation time (range: 4.92-17.08%). However, from 7 to 9 months of age during the winter, social play decreased gradually before rising again from 10 months of age in the spring. Play behavior in infant snub-nosed monkeys is influenced by environmental temperature. Males were observed to play more than females, although further data on this are required. Social rank did not influence the social play of wild Sichuan snub-nosed monkey infants.     

白马雪山自然保护区响古箐滇金丝猴活动时间分配

2008 年6 月至2009 年5 月,在白马雪山国家级自然保护区南端的响古箐(北纬27°37′,东经99°22′),采用瞬时扫描取样法对一群数量约480 只的滇金丝猴群的活动时间分配进行了研究。研究期间共观察取样1 609 h,扫描个体数为260 546。研究表明,响古箐滇金丝猴用38.8% 的时间取食、27. 4% 的时间移动、20. 9%的时间休息、12.9% 的时间从事其他类型活动。滇金丝猴活动时间分配季节性差异明显。冬季,滇金丝猴的取食时间长于其他季节,达到41. 5% ;秋季,取食时间在全年最短(36.5% )。夏季的高温没有影响滇金丝猴的移动,它们移动的时间达到32.8% ,高于其他3 个季节。寒冷的冬季,响古箐滇金丝猴为了减少能量损失,用于休息的时间达到24.4% 。秋季,滇金丝猴从事其他类型活动的时间(15.7% )多于另外3 个季节。研究发现,
绝对移动时间与昼长和月平均温度呈明显正相关(P < 0. 01),绝对休息时间与月平均温度呈负相关(r =- 0. 585,P = 0.046),但降水量的多少与猴群各种活动时间分配之间没有明显的相关性(P > 0.05)。食物贡献率与滇金丝猴日活动时间分配也存在相关性。取食松萝比例与猴群移动时间呈负相关(r = - 0.902,P <0.001),与休息时间呈正相关(r = 0.860,P < 0.001)。猴群取食树叶比例增加时,它们移动时间也随之增加(r = 0.832,P = 0.001)。夏季,滇金丝猴取食竹笋的比例增加时,猴群移动时间也明显增多。以上结果表明,滇金丝猴活动时间分配受食物资源状况、昼长季节性变化和气候条件的影响。     

Workload of general practitioners before and after the new contract.

OBJECTIVE--To assess changes in general practitioners'' workload associated with the new contract introduced in April 1990. DESIGN--Weekly workload diary completed during four weeks in February-March 1990 and during the same period in 1991. SETTING--Sheffield, United Kingdom. SUBJECTS--All 300 general practitioners on Sheffield Family Health Services Authority list as principals in 1990 and 1991. MAIN OUTCOME MEASURES--Mean number of hours worked per week, number of patients seen each week, and mean time spent per patient. RESULTS--181 (60%) general practitioners responded in 1990 and 163 (54%) in 1991. Of these, 18 (10%) were not working in 1990 and 14 (7%) in 1991. General medical service work increased during a "normal working week" from a mean of 38.6 hours a week in 1990 to 40.6 hours in 1991, and non-general medical service work decreased from 5.4 hours a week to 4.5 hours. Hours spent on call were similar before and after the contract. For the 99 general practitioners who responded in both years, time spent on general medical service duties increased significantly (40.5 h in 1990 v 42.5 h [corrected] in 1991; p = 0.033), mainly due to more time being spent in clinics. Significantly more patients were being seen in clinics (9 v 14; p = 0.001); the average time spent per patient remained at about 8 1/2 minutes during surgeries and 16 minutes for a home visit, and rose from 13 to 14 minutes for patients seen in clinics. The time spent on practice administration fell but not significantly. CONCLUSION--Since the new contract there has been a significant increase in general medical services work, mainly due to more patients being seen in clinics, with no reduction in the time spent per patient.     

Effect of forage particle length on rumen fermentation,sorting and chewing activity of late-lactation and non-lactating dairy cows

The objective of this study was to determine the effects of varying forage particle length on chewing activity, sorting behavior, rumen pH and rumen fill in late lactation and dry dairy cattle, fed rations with similar physically effective NDF but different mean particle length. Treatments consisted of three diets differing only in geometric mean length of forage: hay (5.40, 8.96 and 77.90 mm, for short (S), medium (M) and long (L) diets, respectively) for Experiment 1 (E1), and straw (10.16, 24.68 and 80.37 mm) for S, M and L diets, respectively, for Experiment 2 (E2). Hay or straw comprised the sole source of forage (50% and 75% of ration dry matter (DM) for E1 and E2, respectively). Both experiments used three rumen cannulated Holstein dairy cows, in late lactation for E1 and dry in E2, with 3 × 3 Latin square designs with 14 day periods. In E1, DM intake (DMI; 18.3 ± 2.1 kg/day; mean ± s.e.), pH (6.4 ± 0.1), time spent eating (280 ± 22.5 min/day), time spent ruminating (487 ± 17 min/day), and total time spent chewing (767 ± 34 min/day) were not different, whereas eating minutes per kilogram of DMI and NDF intake (NDFI) tended to increase linearly as forage length increased. Rumen digesta volume (l; 113.3 S, 117.8 M and 114.4 L ± 17.1) had a quadratic response, and rumen digesta weight tended to respond quadratically; however, differences were numerically small. In E2, DMI (8.3 ± 1.3 kg/day), pH (6.7 ± 0.1), time spent eating (236 ± 23.5 min/day), time spent ruminating (468 ± 45.2 min/day), total time spent chewing (704 ± 67.7 min/day) and minutes per kilogram NDFI were not different, whereas minutes per kilogram of DMI had a trend for a quadratic effect. Rumen digesta volume (111 ± 18.8 l) and weight (103 ± 17.4 kg) were not different. In both experiments, cows sorted against longer particles as determined by a particle length selection index; this behavior increased linearly as particle length increased. Greater forage particle length increased sorting behavior, but had no effect on rumen fermentation or chewing behavior.     

The Effect of Climatic Factors on the Activity Budgets of Barbary Macaques (Macaca sylvanus)

Climatic conditions can significantly affect the behavior of animals and constrain their activity or geographic distribution. Barbary macaques (Macaca sylvanus) are one of the few primates that live outside the tropics. Here we analyze if and how the activity budgets of Barbary macaques are affected by climatic variables, i.e., air temperature, relative humidity, rainfall, and snow coverage. We collected scan sampling data on the activity budgets of four groups of macaques living in the Middle Atlas Mountains of Morocco from June 2008 to January 2011. This habitat is characterized by extreme seasonal changes, from cold and snowy winters to hot and dry summers. The activity budgets of the macaques differed across months but not across the time of day (with the exception of time spent feeding). The monkeys spent significantly more time feeding or foraging when there was no snow than when snow coverage was moderate or major. Daily rainfall was positively related to resting time and negatively to time spent moving or in social behavior. Air temperature was negatively related to time spent feeding or foraging. Finally, time spent on social behavior was significantly lower when relative humidity was high. These data indicate that environmental factors significantly affect the time budgets of endangered Barbary macaques, a species that has been little studied in the wild. Our findings support previous studies on temperate primates in showing that snow coverage can have negative consequences on the feeding ecology and survival of these species.     

Grooming in brown howler monkeys,Alouatta fusca

The grooming behavior of a group of brown howler monkeys was studied for one year in an Atlantic forest reserve of southeastern Brazil. A total of 290 grooming bouts were recorded and analyzed. The two adult females directed most of the grooming (91%), while the adult male was the major recipient (37%). Grooming between females, and between them and their siblings, also occurred quite often. On average, the group spent 2% of its daily time grooming, with a higher frequency around noon. There were significant differences, however, in time spent grooming between seasons; grooming was more abundant during the coldest seasons (autumn–winter) and rarer in hotter ones (spring–summer). A significant negative correlation was found between grooming time and temperature, but contrary to expectations, grooming time failed to correlate with both the group' diet and the demands of food-gathering, as measured by travelling time and day range length. A comparison of grooming behavior with other species of the genus suggests that brown, red (A. seniculus), and black howler monkeys (A. caraya) are more similar to each other than to mantled howlers (A. palliata), a result that probably is linked with the differing social structure and group size of the latter species. © 1995 Wiley-Liss, Inc.     

滇金丝猴雌性个体间的理毛行为

相互理毛行为广泛存在于社会性群居灵长类动物中,通常具有清洁卫生和社会交往功能。2012 年10 月至2013 年6 月,我们在云南白马雪山国家级自然保护区对一人工辅助投食滇金丝猴群,采用全事件取样法和焦点动物取样法收集了雌性个体间相互理毛的行为数据,包括理毛的部位、理毛的姿势、理毛的时间和回合数。研究结果表明:滇金丝猴雌性个体之间每次相互理毛的平均时间为5. 7 min。相互理毛部位较多的发生在自我理毛不能进行(达到)的部位(61.1% );在不能自我理毛部位的相互理毛行为持续时间长,平均9.7 min;在个体能够进行自我理毛部位的相互理毛持续时间短,平均为3. 2 min。相互理毛的姿势以对坐为主(48. 4% ),不同理毛姿势的理毛时间差异显著。新迁入家庭单元的雌性个体为理毛的首先发起者,但其获得被理毛的时间却并不多。滇金丝猴雌性个体相互理毛部位、理毛姿势和理毛时间的差异表明,它们之间的相互理毛行为符合卫生功能假说和社会功能假说。     

Locomotory activity of captive Cryptomys hottentotus, (Mammalia: Bathyergidae), a fossorial rodent

Locomotory activity of six mole-rats kept singly and in various sized groups was monitored for a total of 1728 hours by use of photocells, event recorder, and a 21 metre long, transparent burrow system. Movement in tunnelways was recorded for all hours of a 24 hour period. Locomotory activity for individuals and a two member group average14–24% of the total time, while a four member group averaged 57% of the total time. Approximately five rest periods per day averaged 50 minutes duration each. The effects of social isolation, burrow length, diet, and individual variation on locomotory activity of fossorial mammals are discussed.     

Sociability in Old Female Japanese Monkeys: Human versus Nonhuman Primate Aging

Over a period of 20 months, 18 aged and 22 non-aged semi-free ranging female Japanese monkeys were observed, and a total of 440 hours of focal animal data were collected. The goal of the study was to investigate the reported pattern of disengagement in old female monkeys. For each subject female, two sociability scores were calculated: the total number of other animals with whom time was spent in affiliative social interaction, and the total amount of time spent in affiliative social interaction. These data were analyzed in order to determine any change in sociability based on age. No relationship was found between age and sociability. The absence of a pattern of decreased social interaction with advancing age in these monkeys is discussed in terms of the methodological differences with earlier studies. It is suggested that the life of nonhuman primates may be essentially continuous from the attainment of adulthood to death, with no recognizable social stage for the elderly, at least in terms of sociability and isolation. Menopause, awareness of mortality, and interindividual dependence are three elements of the human life course that appear to be absent in this troop of Japanese monkeys, and these are discussed as key elements that may render the later portion of the human life course to be very different from that of monkeys, and possibly from that of all other primates.     

滇金丝猴0 - 3 岁个体的社会玩耍行为

2012 年7 月到2013 年4 月,对云南白马雪山国家级自然保护区一个人工辅助投食的滇金丝猴群进行观察,采用全事件取样法对该群全部0-3 岁30 只个体(雄性12 只、雌性18 只) 的社会玩耍行为进行了研究。研究结果表明:不同年龄段的社会玩耍频次存在显著差异,且玩耍频次与年龄段呈明显负相关;0-3 岁的滇金丝猴倾向于选择相同年龄段的个体作为玩耍伙伴;0-1 岁的个体更喜欢追逐(67.5%) 的玩耍行为,1-2 岁内的个体主要采取抓打(26.6% )、撕咬(25.3% )、追逐(40.5% )的玩耍行为;2 -3 岁的个体各种玩耍行为的频次有明显差异。0-3 岁的雄性个体比雌性个体的玩耍频次更高。研究结果表明,0-3 岁滇金丝猴的社会玩耍行为符合年龄阶段假说、性别差异假说和运动技能训练假说。     

Spatial and Temporal Activity Patterns of the Free-Living Giant Mole-Rat (Fukomys mechowii), the Largest Social Bathyergid

Despite the considerable attention devoted to the biology of social species of African mole-rats (Bathyergidae, Rodentia), knowledge is lacking about their behaviour under natural conditions. We studied activity of the largest social bathyergid, the giant mole-rat Fukomys mechowii, in its natural habitat in Zambia using radio-telemetry. We radio-tracked six individuals during three continuous 72-h sessions. Five of these individuals, including a breeding male, belonged to a single family group; the remaining female was probably a solitary disperser. The non-breeders of the family were active (i.e. outside the nest) 5.8 hours per 24h-day with the activity split into 6.5 short bouts. The activity was more concentrated in the night hours, when the animals also travelled longer distances from the nest. The breeding male spent only 3.2 hours per day outside the nest, utilizing less than 20% of the whole family home range. The dispersing female displayed a much different activity pattern than the family members. Her 8.0 hours of outside-nest activity per day were split into 4.6 bouts which were twice as long as in the family non-breeders. Her activity peak in the late afternoon coincided with the temperature maximum in the depth of 10 cm (roughly the depth of the foraging tunnels). Our results suggest that the breeding individuals (at least males) contribute very little to the work of the family group. Nevertheless, the amount of an individual''s activity and its daily pattern are probably flexible in this species and can be modified in response to actual environmental and social conditions.     

Effect of habitat quality on the ecological behaviour of a temperate-living primate: time-budget adjustments

Barbary macaques, like other non-human primates living in highly seasonal temperate environments, display high monthly variations in their diet. In addition, their diet changes according to the habitat type they colonize and to the degree of habitat degradation due to resource exploitation by local people, in particular through pastoralism. We studied the time-budget adjustments of wild Barbary macaques in three cedar–oak forests impacted by different intensities of grazing pressure from goats and sheep. We examined how diet variations influenced the time monkeys spent in their activities and their day range lengths (i.e. their energy costs). At three studied sites, diet composition and time budgets showed marked seasonal variations. Diet composition had a strong influence on monkeys’ time budget. In the forest where pastoralism was the highest, diet included a greater proportion of underground resources, shrub fruit and acorns, which led to an increase in the time spent foraging and moving, as well as an important increase in day range lengths. Energy costs were therefore higher in a degraded environment than in a suitable habitat. The monkeys living in forests subjected to pastoralism took advantage of increased day lengths to spend more time searching for food. However, in the forest with the highest pastoralism pressure, although monkeys spent more time foraging, they spent less time feeding than monkeys at the other sites. In addition, they appeared to have reached the limits of the available time they could devote to these activities, as their diurnal resting time was at its lowest level over several months. Temperature variations did not appear to modify monkeys’ time budgets. In the least favourable habitat, saving time from resting activity allowed monkeys to maintain a relatively high level of social activity, partly linked to rearing constraints.     

Increased aggressive behavior and decreased affiliative behavior in adult male monkeys after long-term consumption of diets rich in soy protein and isoflavones

Estrogen produced by aromatization of gonadal androgen has an important facilitative role in male-typical aggressive behavior that is mediated through its interaction with estrogen receptors (ER) in the brain. Isoflavones found in soybeans and soy-based dietary supplements bind ER and have dose- and tissue-dependent effects on estrogen-mediated responses. Yet, effects of isoflavone-rich diets on social and aggressive behavior have not been studied. We studied the effects of long-term (15 months) consumption of diets rich in soy isoflavones on spontaneous social behavior among adult male cynomolgus macaques (Macaca fascicularis) (n = 44) living in nine stable social groups. There were three experimental conditions which differed only by the source of dietary protein: casein and lactalbumin (no isoflavones), soy protein isolate containing 0.94 mg isoflavones/g protein, and soy protein isolate containing 1.88 mg isoflavones/g protein. In the monkeys fed the higher amount of isoflavones, frequencies of intense aggressive (67% higher) and submissive (203% higher) behavior were elevated relative to monkeys fed the control diet (P's < 0.05). In addition, the proportion of time spent by these monkeys in physical contact with other monkeys was reduced by 68%, time spent in proximity to other monkeys was reduced 50%, and time spent alone was increased 30% (P's < 0.02). There were no effects of treatment on serum testosterone or estradiol concentrations or the response of plasma testosterone to exogenous gonadotropin-releasing hormone (GnRH). The results indicate that long-term consumption of a diet rich in soy isoflavones can have marked influences on patterns of aggressive and social behavior.