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51.
Aging and fertility patterns in wild chimpanzees provide insights into the evolution of menopause 总被引:2,自引:0,他引:2
Emery Thompson M Jones JH Pusey AE Brewer-Marsden S Goodall J Marsden D Matsuzawa T Nishida T Reynolds V Sugiyama Y Wrangham RW 《Current biology : CB》2007,17(24):2150-2156
Human menopause is remarkable in that reproductive senescence is markedly accelerated relative to somatic aging, leaving an extended postreproductive period for a large proportion of women. Functional explanations for this are debated, in part because comparative data from closely related species are inadequate. Existing studies of chimpanzees are based on very small samples and have not provided clear conclusions about the reproductive function of aging females. These studies have not examined whether reproductive senescence in chimpanzees exceeds the pace of general aging, as in humans, or occurs in parallel with declines in overall health, as in many other animals. In order to remedy these problems, we examined fertility and mortality patterns in six free-living chimpanzee populations. Chimpanzee and human birth rates show similar patterns of decline beginning in the fourth decade, suggesting that the physiology of reproductive senescence was relatively conserved in human evolution. However, in contrast to humans, chimpanzee fertility declines are consistent with declines in survivorship, and healthy females maintain high birth rates late into life. Thus, in contrast to recent claims, we find no evidence that menopause is a typical characteristic of chimpanzee life histories. 相似文献
52.
Two high-ranking adult male chimpanzees (Pan troglodytes) of M group in the Mahale Mountains National Park, Tanzania, tried to get a newborn female infant of an adult female who
was born in M group. The mother was not seen to mate with these adult males during the probable conception cycle of the infant,
but she disappeared from the group during the later cycle, when she may have been inseminated by a male of one of the neighboring
unit groups. The adult males failed to get the infant because the grandmother of the newborn and her female friend cooperated
to protect the mother and infant from attacks by the males. The sexual selection hypothesis for infanticide by adult male
chimpanzees holds for this observed case. The sudden disappearance of another infant, a healthy female, strongly suggests
the killing of female infants too. Therefore, the asserted male-biased infanticide in chimpanzees appears to be less tenable. 相似文献
53.
In the Mahale Mountains National Park, Tanzania, a young adult male chimpanzee was observed to feed on a 3-month-old male
infant of the same unit-group. Four other adult males and an adult female shared the carcass. The mother of the victim had
immigrated from a neighboring unit-group four years previously. Circumstantial evidence strongly suggests that the first-observed
cannibal male also killed the infant. The adult male and the mother of the victim had been familiar socially and sexually
with each other since the female immigrated. Since the mother of the victim had usually been ranging in the peripheral part
of the unit-group's range, i.e., the overlapping area of the two unit-group's ranges during pregnancy and soon after birth,
the infanticidal male might have had reason to suspect the paternity of her infant. Four such cases of within-group cannibalism
by adult males suggest that the female range and association pattern before and after parturition are key factors allowing
an infant to survive. The possibility of male-biased infanticide is also discussed. 相似文献
54.
55.
56.
Michio Nakamura William C. McGrew Linda F. Marchant Toshisada Nishida 《Primates; journal of primatology》2000,41(3):237-248
Chimpanzees (Pan troglodytes schweinfurthii) in the Mahale Mountains National Park, Tanzania, scratch other individual's bodies while they groom them. This behavioral
pattern of “social scratch” is another example of locality-specific social behavior, or custom, as it is not found in the
Gombe National Park, Tanzania, about 150 km north of Mahale, nor has it been reported from any other sites of chimpanzee study.
Frequency of social scratch was correlated with frequency of social grooming, but not with frequency of self-scratch. Frequencies
of social scratch per grooming bout among adult and adoles-cent males, and from lactating females to infants or juveniles,
were high, and among males, higher-ranking males especially received more. These facts indicate some social function of the
behavior. Social scratch was directed mostly to the dorsal side of the body. However, when lactating females social scratched
to infants or juveniles, they scratched other body parts. Social scratch was not lateralized to left or right. We present
four hypotheses on the functional origin and on the learning process of this cultural behavioral pattern. 相似文献
57.
58.
In many genetic studies on the great apes, fecal or hair samples have been used as sources of DNA. However, feces and hairs
are difficult to collect from chimpanzee infants under 3 years of age. As alternative DNA sources, we investigated the efficiency
of collecting urine samples from infants compared with fecal samples, as well as the validity of the DNA extracted from urine
and saliva samples of well-habituated M group chimpanzees (Pan troglodytes schweinfurthii) in the Mahale Mountains National Park, Tanzania. We collected 40 urine and 3 fecal samples from 10 infants under 3 years.
Compared with feces, the urine samples were relatively easy to collect. The saliva of infants, which remained on the twigs
sucked by them, was collected using cotton swabs. The average amounts of DNA extracted from the 40 urine and 6 saliva samples
were 3,920 and 458 pg/μl, respectively. The rate of positive PCR was low and the allelic dropout rate was high when using
less than 25 pg of template DNA in the PCR mixtures. Based on the amounts of DNA, 50% of the urine samples and 100% of the
saliva samples were judged usable for accurate microsatellite genotyping. For infant chimpanzees in particular, collecting
urine and saliva as an alternative to fecal and hair samples can reduce the effort invested in collection in the field. 相似文献
59.
This study, based on 687 hr of focal observations, aims to describe overall patterns of the sexual behavior of the adult male
chimpanzees of the Mahale Mountains, to compare the results with previous reports, and to explain the variations between studies.
Genital inspection of cycling females by adult males was eight times as frequent as that of lactating females, and twice as
frequent as that of pregnant females. Inspection of the genitals of cycling females increased dramatically 7–10 days before
the onset of maximal swelling and gradually decreased as the day of ovulation approached. Adult males likely obtained information
on the attractivity of females by inspecting their genitals. Mating was usually initiated by male courtship and followed by
pelvic thrusts in a dorsoventral posture, performed on, rather than above, the ground, which continued for 7 s. on average,
and was typically followed by female squeaking and darting from the male, or by the male grooming the female. Higher-ranking
males mated with females in the peri-ovulatory period more frequently than did lower-ranking males. In particular, two alpha
males mated with such females more often than did any other adult males. A male who interfered with a mating pair was dominant
over the mating male in other agonistic contexts. The duration of intromission was correlated with neither dominance rank
nor age. However, when an adult male declined in rank from alpha in 1991 to third in 1992, he showed a significantly shorter
duration of intromission. This indicates that for a particular male, the alpha rank guaranteed longer duration of intromission.
Allies of alpha males tended to mate with peri-ovulatory females more frequently than expected from their low dominance ranks.
The number of mating partners was not correlated with male dominance rank, but was sometimes negatively correlated with male
age. Females were significantly more likely to emit a copulatory squeak when mating with younger, rather than older, adult
males. Male dominance rank and the rate of female copulatory squeaking were not correlated. Weaning infants regularly interfered
with their mothers' mating. Occasionally, unrelated adolescent males and rarely females pushed themselves in between copulating
adults. Female choice was indicated when they performed a “penis erection check” or took the initiative in courtship, or on
the other hand showed strong reluctance to mate with particular males. Young adult males more often received erection checks
than did prime males, while none of the three old adult males did. Courtship initiated by estrous females was not directed
to two of the oldest males, the exception of which was the alpha male. The oldest males, except for the alpha, were consistently
avoided by many estrous females, both young and old. In response to female reluctance, males behaved violently, however, this
was not effective, because other more dominant males came to rescue the female. Neither courtship nor mating was seen between
mature sons and their mothers, nor between brothers and sisters. 相似文献
60.
The social group of wild chimpanzees in the Mahali Mountains 总被引:7,自引:0,他引:7
Toshisada Nishida 《Primates; journal of primatology》1968,9(3):167-224
There are more than six large groups of wild chimpanzees in the study area, which is in the north-eastern part of the Mahali Mountains of Western Tanzainia. One of these groups was provisionized, that is, customarily fed sugar cane and bananas. The characteristics of the social group of wild chimpanzees are clarified by long-term observation of the baited population. The chimpanzees live in a clear-cut social unit which consists of adult males, adult females, and immature animals. The permanency, stable membership, and integrative nature of the unit-group were confirmed during the course of this study. The size of unit-groups ranges from 30 to 80 head.The unit-group generally splits up into temporary subgroups that repeat joining and parting. The size of the subgroups of the baited population ranges from one to 28 head, the mean being 8.1 head. The centralization of a unitgroup is mainly sustained by the high sociability of adult males. The random nature of the membership of subgroups is emphasized in this paper, although subgroups are usually composed by social bonds on the basis of similar age, sex, blood relationship, and/or sexual attraction.The inter-unit-group interaction is peaceful; the subordinate unit-group avoids the dominant one. The home ranges of unit-groups overlap each other extensively, the overlapping areas being used flexibly by both unit-groups on the basis of dominance-subordination relationship. The member-exchange among unit-groups may sometimes occur, but the extent of openness or closedness of a unit-group has not been well elucidated.The research has been financed by the Scientific Research Fund of the Ministry of Education and in part by the Wenner-Gren Foundation. 相似文献