ISSN:0275-2565    

DOI:10.1002/ajp.1350220402

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe movement patterns of the joints of the right hind limbs and forelimbs of four vervet and one squirrel monkey were compared during right‐ and left‐lead gallops. Although the overall displacement patterns were similar under both conditions, comparisons of the inflection points in the curves yielded consistent differences in the joints at various phases in the cycle. Some of these differences appear to reflect differing mechanical conditions, whereas others seem to represent variation in muscle activation patterns. Although some of the differences in the joints under the two conditions were consistent with those reported previously for other quadrupeds, others were not. This may reflect that different quadrupeds use slightly different biomechanical strategies during gallop

ISSN:0275-2565    

DOI:10.1002/ajp.1350220403

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

年代:1990

数据来源: WILEY

摘要:

AbstractData obtained over a 7.5 year period from a captive group of sooty mangabeys were analyzed to examine the relationship between demographic variables and reproductive events. Perineal swelling and reproductive data collected from 67 females contributed to the analyses. Sexual maturation, as marked by the onset of swelling cycles, was recorded at an average age of 36.4 ± 1.1 (mean ± SEM) months and first parturition at 56.5 ± 1.8 months, indicating a period of adolescent sterility of over 1 year. A total of 198 births were recorded, of which 165 (83.3%) were live births with infant survival to 30 days of age. Both parity and the duration of infant survival influenced interbirth interval, with the shortest interval observed in multiparous females with infants surviving less than 6 months (10.0 ± 0.5 months) and the longest in primiparous females with infants surviving more than 12 months (22.4 ± 1.2 months). Infant survival did not vary significantly according to the age class of the mother. Births and the onset of perineal swellings in young females showed a seasonal distribution, with swelling cycles and conceptions rarely occurring from April through Septe

ISSN:0275-2565    

DOI:10.1002/ajp.1350220404

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

年代:1990

数据来源: WILEY

摘要:

AbstractIn addition to a variety of calls whose functions are to increase or decrease space among individuals, many species of primates use one or more vocalizations that are emitted in no one particular context and elicit no one particular response. Although investigators have given this type of vocalization a number of different names (e.g., contact call, cohesion call), what these calls seem to have in common is that 1) they allow individuals to monitor the general whereabouts of groupmates and 2) they somehow contribute to group cohesion. Neither of these assumptions has been tested, however. In the red‐bellied tamarin(Saguinus labiatus), a vocalization we call the “slide” appears to be a monitoring call. In the current study we tested three hypotheses about the slide call: 1) If slide calls are not direct requests for action, there should be no reliable correlation between slide calls and movement toward or away from the slide caller; 2) if slide calls are emitted to monitor groupmates' whereabouts, they should occur at comparatively low rates when the presence of groupmates can easily be affirmed by visual means (e.g., when the animals are confined in a small space); 3) if slide calls contribute to intragroup cohesion, they should be produced at comparatively high rates during activity that requires coordinated behavior. Each of these predictions was supported. Although variants of the call and/or additional functions of the call(s) may emerge from further testing, social monitoring appears to be at least one important function of the slide calls of red‐bellied tamarins, especially in circumstances where coordinated and/or cohesive behavior is required of th

ISSN:0275-2565    

DOI:10.1002/ajp.1350220405

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe didelphidCaluromysshows evolutionary convergence towards prosimians in having a relatively large brain, large eyes, small litters, slow development, and agile locomotion. The selection pressures that favored the emergence of primate‐like traits inCaluromysfrom a generalized didelphid ancestor may be analogous to the selection pressures favoring the initial divergence of primates from a primitive nonprimate ancestor, and thusCaluromysprovides an independent test of the arboreal hypothesis (Smith:Annual Report of the Board of Regents of the Smithsonian Institution1912:553–572, 1913), the visual predation hypothesis (Cartmill:The Functional and Evolutionary Biology of Primates, pp. 97–122, 1972), and the angiosperm exploitation hypothesis (Sussman:American Journal of Primatology, in press) of primate origins. Quantitative data on free‐rangingC. derbianusin Costa Rica demonstrate that it is highly arboreal, uses visually directed predation to capture arthropod prey, and makes extensive use of terminal branch foraging, where it feeds on small angiosperm products. These observations are consistent with predictions from each model of primate origins, thus suggesting that the hypotheses are not mutually exclusive but are interdependent. The initial divergence of primates probably involved exploitation of the rich angiosperm products and associated insects found in fine terminal branches; visually directed predation may have evolved as an efficient method of insect capture in the terminal branch

ISSN:0275-2565    

DOI:10.1002/ajp.1350220406

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

年代:1990

数据来源: WILEY

摘要:

AbstractAnalysis of long‐range vocalizations given by spider monkeys revealed consistent acoustic differences among the calls of individuals. Of seven acoustic measurements, four exhibited significant variation between individuals. A discriminant analysis demonstrated that two of these variables allowed correct identification of the caller 44% of the time. Including the remainder of the variables increased the percentage correctly identified to 50%. Individual identification by call structure could benefit spider monkeys, where individuals forage separately in subgroups and the interactions between specific pairs of individuals is highly variable. Acoustic recognition of callers would facilitate the choice of which subgroups to join, thus allowing individuals to manipulate the size and composition of their subgroups. In addition, the calls of mothers and offspring appeared to be similar in acoustic propertie

ISSN:0275-2565    

DOI:10.1002/ajp.1350220407

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

年代:1990

数据来源: WILEY

摘要:

AbstractMean gestation for seven free‐ranging Tana River crested mangabeys(Cercocebus galeritus galeritus)is 180 days (SE = 4.49). All females showed postconception sexual swellings after the first 2 months of pregnancy, and two of the seven copulated with males at this time. One birth was observed; observations of a second infant began less than 1 hr after birth. Details of parturition are given, with responses of group members to the events. Adult and juvenile females showed more sustained interest in the new infants than adult or juvenile male

ISSN:0275-2565    

DOI:10.1002/ajp.1350220408

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

年代:1990

数据来源: WILEY

ISSN:0275-2565    

DOI:10.1002/ajp.1350220409

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

年代:1990

数据来源: WILEY

ISSN:0275-2565    

DOI:10.1002/ajp.1350220410

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

年代:1990

数据来源: WILEY

ISSN:0275-2565    

DOI:10.1002/ajp.1350220411

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

年代:1990

数据来源: WILEY