摘要:

Forests of Ankarana limestone massif in northern Madagascar support one of the largest and least disturbed populations of Crowned Lemurs, Lemur coronatus. This paper reports a preliminary study of the ecology of this species in the Ankarana Special Reserve conducted at the end of the dry season in 1986, with additional information collected a year later. Crowned Lemurs occur in very high densities in the semi-deciduous canopy forest and this probably represents a dry season refuge for the species. They also use more open habitats, including sparsely vegetated limestone and degraded forest. Sanford’s Lemur, Lemur fulvus sanfordi, also inhabits the Ankarana forests but is most abundant in degraded habitats. Crowned and Sanford’s Lemurs had similar patterns of activity, which included nocturnal travelling and feeding bouts. Crowned Lemurs proved to be unusual among Lemur species in displaying low spatial troop cohesion and a lack of obvious troop hierarchy. Strongyloides-like enteric helminths infested about one third of Crowned Lemurs but were apparently not causing disease. Crowned Lemurs fall prey to the Fosa, Cryptoprocta ferox, and the young possibly also to the largest raptors. A total of seven living lemur species (including the very rarePropithecus diadema perrieri and Daubentonia madagascariensis) were confirmed at Ankarana by the authors, and three further species have been reported by other observers. In addition to these ten extant lemurs, four subfossil species have been discovered: three of them (Hapalemur simus, Palaeopropithecus and Mesopropithecus) by theauthors. The possibility that all 14 lemurs were once sympatric is discussed. For the present, the lemurs of Ankarana are protected from hunting by local taboo. Nevertheless they are under severe threat from habitat destruction, despite Ankarana’s Special Reserve status. Given the very restricted distributions of Crowned and Sanford’s Lemurs, both must be considered as threatened with ext

ISSN:0015-5713    

DOI:10.1159/000156379

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

This paper presents comparative data on the vocal communication of two Asian leaf monkeys, the Nilgiri langur (Presbytis johnii) and South Indian common langur (Presbytis entellus), based on sound recordings and behavioural observations of free-ranging groups. Spectrographical analyses revealed a repertoire of 18 basic patterns for Nilgiri langurs, and 21 basic patterns for common langurs. The repertoires of the two langur species consist of both discretely structured vocal patterns, in which alterations of the physical parameters are restricted to intra-class variation, and those in which structural variations cause intergradation between different sections of the repertoire. Qualitative assessments of group scans indicate that in both species vocal behaviour is characterized by pronounced sex-differences in the use of the different elements of the vocal repertoire. Comparison of data available from different populations of P. entellus suggests population-specific modifications on both structural and behavioural levels. Moreover, characteristic elements of the vocal systems of the two Asian species demonstrate striking similarities to those described for the African black-and-white colobus.

ISSN:0015-5713    

DOI:10.1159/000156380

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The external dimensions of the limb bones and the geometry of their midshaft cross-sections were determined for Loris tardigradus and Nycticebus coucang. Relative cortical thickness, cortical area, and second moment of area were calculated and contrasted with locomotor stresses. The difference in shape-related strength of the bones between the smaller- and the larger-bodied species is more pronounced than can be expected from stresses acting during normal locomotion. The Nycticebus skeleton has a much higher safety margin overall and seems to be dimensioned for infrequent but critical stresses of high magnitude. Lorisine gaits in general are characterized by low ground reaction forces, great mobility in all joints, and a nearly equal share in propulsion and weight-bearing by the fore- and hindlimb. Accordingly, the long bones of lorises (especially those of L. tardigradus) tend to be less rigid than those of other mammalian species (including other primates), they lack a preferential plane of higher bending strength, and femur and humerus do not differ markedly in their capacity to withstand mechanical stresses. External dimensions of the humerus and femur of the two African lorisine species parallel and corroborate these results. Some more general implications for the relationships between bone shape and locomotor stresses are also discussed.

ISSN:0015-5713    

DOI:10.1159/000156381

出版商:S. Karger AG    

年代:1989

数据来源: Karger

ISSN:0015-5713    

DOI:10.1159/000156382

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Data were collected on one group of muriquis, or woolly spider monkeys (Brachyteles arachnoides) during a 14-month study at Fazenda Monies Claros, Minas Gerais, Brazil to examine the effects of food patch size on muriqui feeding associations. Muriqui food patches were larger than expected from the availability of patch sizes in the forest; fruit patches were significantly larger than leaf patches. Feeding aggregate size, the maximum number of simultaneous occupants, and patch occupancy time were positively related to the size of fruit patches. However, a greater number of individuals fed at leaf sources than expected from the size of these patches. Adult females tended to feed alone in patches more often than males, whereas males tended to feed in single-sexed groups more often than females. Yet in neither case were these differences statistically significant.

ISSN:0015-5713    

DOI:10.1159/000156383

出版商:S. Karger AG    

年代:1989

数据来源: Karger

ISSN:0015-5713    

DOI:10.1159/000156384

出版商:S. Karger AG    

年代:1989

数据来源: Karger

ISSN:0015-5713    

DOI:10.1159/000156385

出版商:S. Karger AG    

年代:1989

数据来源: Karger

ISSN:0015-5713    

DOI:10.1159/000156386

出版商:S. Karger AG    

年代:1989

数据来源: Karger

ISSN:0015-5713    

DOI:10.1159/000156387

出版商:S. Karger AG    

年代:1989

数据来源: Karger

ISSN:0015-5713    

DOI:10.1159/000156388

出版商:S. Karger AG    

年代:1989

数据来源: Karger