Universitas Nasional

About: Universitas Nasional is a education organization based out in Jakarta, Indonesia. It is known for research contribution in the topics: Population & Computer science. The organization has 974 authors who have published 979 publications receiving 6511 citations.

Orangutan Cultures and the Evolution of Material Culture

Abstract: Geographic variation in some aspects of chimpanzee behavior has been interpreted as evidence for culture Here we document similar geographic variation in orangutan behaviors Moreover, as expected under a cultural interpretation, we find a correlation between geographic distance and cultural difference, a correlation between the abundance of opportunities for social learning and the size of the local cultural repertoire, and no effect of habitat on the content of culture Hence, great-ape cultures exist, and may have done so for at least 14 million years

Party size and early detection of predators in sumatran forest primates

Abstract: Theoretical considerations suggest that the ability to detect the presence or approach of a predator when there is still enough time to flee (early detection) should improve with group size, if group living is to be advantageous for individual non-human primates. The hypothesis that the distance at which forest primates detect predators increases with the size of their party was confirmed by observation. It was found that in addition to party size height (vegetation density) could also influence detection distance. Because height relates not only to visibility but also to the number of potential predators, one would predict that small parties are found higher in the canopy to compensate for the increased risk of predation. This prediction was confirmed using data on long-tailed macaques (Macaca fascicularis). The correlation found between party size and predation risk demonstrates that forest monkeys can adjust their behaviour in response to changes in predation risk, and hence support the hypothesis that predation risk has been an important, perhaps even the only, selective force responsible for the evolution of group living in non-human primates.

A multi-samples, multi-extracts approach for microsatellite analysis of faecal samples in an arboreal ape

Abstract: We investigated the effect of the number of faecal samples, ofextracts per sample and of PCRs per extract on the reliability ofgenotypes for a microsatellite locus in free-living orang-utans.For each individual 36 PCRs were performed using DNA extractionsfrom up to four faecal samples. We found a very largeinter-individual variation in positive PCRs (P+) (36/36 for oneindividual and 0/36 for another). As many as 30% of the cases ledto erroneous genotypes when only one P+ was obtained. It ispreferable to use at least 4 P+ per extract to reduce thisproportion to less than 1%. With 3 P+ results, erroneousgenotypes were still observed in 26% of the cases together. Theseresults indicate that it is necessary to do a minimum of 4 PCRsper extract. In order to have a chance to observe 4 P+, threeextracts should be ideally analysed for each sample. We alsorecommend that when possible two or more samples should becollected in the field to increase the chance of having extractscontaining DNA and to provide independent replicates. While werecognise the difficulty of working with faecal samples, weadvocate the use of faecal material for genetic studies ofcertain wild animal populations where the advantages of avoidingdisturbance, stress and injury are deemed of critical importance.