摘要:

AbstractDuring a four‐year period at Tanjung Puting Reserve, Central Indonesian Borneo, subadult males were observed for 670.5 observation hours, 463 hours of which were as focal individuals. Subadult males were quite gregarious, participating in groupings for 40.9% of the time they were observed as targets. Subadult male sociality centered around females; 83% of the time subadult males spent in groupings was exclusively with females, as compared to 3% of contact time spent exclusively with other males. Much subadult male sociality can be understood in terms of male‐male competition for females. Interactions between adult and subadult males were almost entirely determined by the presence or absence of females. Adult males were more belligerent when females were present. Twenty‐two copulations or attempted copulations occurred during 16 subadult male‐female encounters, two of which were consortships. The majority of subadult male copulations (86%) were resisted matings. Outside of consortship, resisted matings (or the first in a series of resisted matings or attempts) usually took place at encounter or shortly thereafter. Subadult males also surreptitiously followed adult males and their consorts. Subadults frequently located receptive females before adult males did but were replaced by adult males when these appeared. Subadult male reproductive strategy consisted of both sneak/“rape” and consort tactics with sneak/“rape

ISSN:0275-2565    

DOI:10.1002/ajp.1350080202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe geographic distribution of two congeneric monkeys (Cebus albifronsandC. apella) was studied in El Tuparro National Park in the llanos of eastern Colombia. Extensive trips were undertaken by land and river to collect 268 precisely located groups of these two species. The distributions of these monkeys were generally mutually exclusive and parapatric, contrasting with their known sympatry in closed‐canopy rainforest farther to the south. The replacement of one species by the other was abrupt along the northern water courses in the park; however, the two species' ranges partially overlapped and contained islands of sympatry towards the southern parts of the park, where forests are more extensive. Along the rivers,C. albifronswas found in seasonally inundated forests and woodlands that were seldom entered byC. apella. Such inundatable vegetation was extensive in downriver sites in the typically flat llanos geography of this part of Colombia. Although some differential use of habitat was demonstrated, many forests containing the two species seemed essentially identical so that historical precedence, competition, or both may also be posited to partially explain the distributions, although this remains to be demonstrate

ISSN:0275-2565    

DOI:10.1002/ajp.1350080203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractRepeated censuses of a population of yellow baboons (Papio cynocephalus) in Amboseli National Park, Kenya, revealed a decrease from over 2,500 animals in 1963–1964 to 123 individuals in 1979, or from a density of about 73 to 1.8 baboons per km2over a 15‐year period. Median group size decreased from 43 in 1964 to 27 in 1979. The largest and smallest groups declined the most; groups near the median have maintained fairly stable size and age distributions. The population seemed to have stabilized by 1983 at approximately 150 animals in six groups (median group size 28; density 2.2/km2). Although baboon population and group size appeared to be stable during 1963–1964, the age distribution and demographic parameters (age‐specific mortality and natality for one social group) during that year indicate that the population decline had already started. The rate of population decline was greatest in the 1964–1969 period and remained appreciable during the next 5 years. The decline of the baboon population was paralleled by that of other Amboseli savannah woodland mammalian species and took place during a period of very high mortality of fever trees (Acacia xanthophloea) and extensive invasion of the area by halophytes, a transition brought on by rising ground water and consequent elevation of the soil salinity zone. In this and several other primate populations, mortality of infants and juveniles appears to be the demographic variable most sensitive to environment

ISSN:0275-2565    

DOI:10.1002/ajp.1350080204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractDental dimensions and distributions of dental dimensions of males and females were compared for great apes (Pan, Gorilla, andPongo, and humans (Homo). The results were examined and discussed with reference to fossil primatesSivapithecusandRamapithecus. The analyses focused on patterns of sexual dimorphism, both with regard to mean dimensions and the distribution of those dimensions. Sex differences in mean canine dimensions were large and significant forGorillaandPongo, significant but smaller forPan, and small but occasionally significant forHomo. The dispersions of measures were greater for males than for females inGorillaandPanbut did not differ significantly forPongoorHomo. Examination of the noncanine teeth revealed complex sex differences. In the anterior teeth, sex differences in mean dimensions were generally apparent forGorillaandPongo, less so forPan, and least of all inHomo. The patterns of dispersion of measures of anterior teeth differed markedly from those of the canines.Panexhibited the same pattern for anterior and canine teeth.Gorillashowed the opposite pattern.PongoandHomoshowed similar dispersions for males and females in many cases. Sex differences in posterior teeth followed the pattern of the canines forGorillaand were absent forPan. Pongoexhibited mean differences in dimensions across sex, but dispersions were similar. The pattern forHomowas most like that ofPongo, but with fewer significant differences. The genera differed with regard to the number of significant differences in means or dispersions along the tooth row. It is clear that the patterns of dimorphism differ qualitatively across all extant genera of great apes and humans. It appears that the pattern forHomomost closely resembles that ofRamapithecus, whereasPongomost closely resemblesSivapithecus. The patterns forGorillaandPanappear to be unlike either of the fossil forms. It is suggested that the qualitatively distinct patterns of dental sexual dimorphism indicate substantial flexibility during recent primate evolution and that the degree of structural flexibility demonstrated provides a basis for appreciating potential for plasticity of gender differences in behavioral, social, and cultural systems.

ISSN:0275-2565    

DOI:10.1002/ajp.1350080205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractA breeding colony of slender lorises (Loris tardigradus malabaricus) was studied to obtain data for comparison with other prosimian species, to contribute reproductive information for improving management of captive lorises, and to resolve some uncertainties in the literature regarding reproduction in the slender loris. At the Duke University Primate Center, a female slender loris reached sexual maturity at approximately ten months of age and conceived at one year of age. The length of the estrous cycle was 29–40 days, with copulation occurring over two consecutive days during estrus. Gestation length was 166–169 days. Litter size for each six births was one. Conception did not occur during an immediate post‐partum estrus, but four months after birth, resulting in a 9 1/2‐month interbirth interval. There was no evidence of reproductive seasonality. Lactation lasted between five and seven months. Reproductive rates of slender lorises are among the lowest of primates less than 500 g. Differences in reproductive parameters may exist between different subspecies of slender

ISSN:0275-2565    

DOI:10.1002/ajp.1350080206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractTo examine the effects of ovarian hormones on the behavior of femaleMacaca fascicularisand their male partners, daily 1‐hr behavior tests were conducted while ovariectomized females were (1) untreated, (2) given estradiol benzoate (EB) (5 μg subcutaneously [s.c.]/day), (3) given estradiol benzoate together with increasing doses of progesterone (P) (5 mg, 10 mg, and 20 mg. s.c./day), and (4) given testosterone propionate (TP) (0.25 mg s.c./day) (six pairs, 540 tests). Weekly blood samples were analyzed by radioimmunoassay for plasma hormone levels (81 samples). Estrogen treatment produced plasma estradiol levels similar to those of intact females during the late follicular phase of the menstrual cycle. Additional progesterone at the lowest dose produced plasma progesterone levels similar to or somewhat higher than those during the midluteal phase, while higher doses produced supraphysiological levels. Androgen treatment resulted in plasma levels well above the physiological range. Hormone treatments produced highly significant effects on the sexual, social, and aggressive interactions of the pairs. As in rhesus monkeys, estrogen increased male and female sexual activity, and increasing doses of additional progesterone reversed these effects. Unlike in rhesus monkeys, testosterone propionate increased both female sexual motivation (invitations) and also male sexual activity and ejaculatory performance. The direction of the hormone‐dependent changes in grooming and aggressive interactions confirmed earlier results with intact females and indicated that aggressive interactions and male grooming times were highest, and female grooming times were lowest, when copulatory activity was at its he

ISSN:0275-2565    

DOI:10.1002/ajp.1350080207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe relationship between the growth spurt and the onset of sexual maturity is problematic in nonhuman primates. Growth data on the cranium and postcranium of dentally aged pygmy chimpanzees, common chimpanzees, and gorillas are reported here. In all three species, male means generally exceed female means throughout growth, with the exception that females exhibit a spurt during one dental‐age stage when they become generally larger than the males. This female spurt occurs earlier in an absolute and relative sense in the gorillas than the chimpanzees. These growth data support field and laboratory observations suggesting that female gorillas become sexually mature earlier than do female chimpanzees. Gorillas are thus characterized by a greater degree of “sexual bimaturism” than are the chimpanzees. Implications of these differences in terms of size dimorphism, mating systems, and morphology are disc

ISSN:0275-2565    

DOI:10.1002/ajp.1350080208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

ISSN:0275-2565    

DOI:10.1002/ajp.1350080209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

ISSN:0275-2565    

DOI:10.1002/ajp.1350080210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

ISSN:0275-2565    

DOI:10.1002/ajp.1350080211

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY