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B M Galdikas

Publications and source records attributed to B M Galdikas.

7 recordsLinked to original sources
PubMed2000

mtDNA sequence diversity of orangutans from the islands of Borneo and Sumatra.

A comparison of mitochondrial DNA sequences was undertaken for two genes among orangutans from Borneo and Sumatra. The distribution of haplotypes among 42 individuals for NADH dehydrogenease subunit 3 and 39 individuals for cytochrome B was used to infer population structure. The haplotypes among all Bornean orangutans form a cluster of closely related individuals for both genes, with two distinct haplotypes occupying different regions of the island. Sumatran haplotypes fall into three distinct, and highly diverged, groups. Strikingly, one of the Sumatran haplotypes shares sequence identity with the most widespread Bornean haplotype. This haplotype distribution is considered in the context of the highly complex geological history for the area around the Malay Archipelago. Alternating periods of geographic isolation and reunion, resulting from glacially induced land bridge formation, presented substantial opportunity for population dispersal between periodically isolated demes. We present a paleodispersal model that is consistent with genetic, geological, paleoecological, and fossil data. The disparity of sequences present in orangutan populations argues against a simple Sumatra-Borneo dichotomy. Our evidence, and that of others, suggests that the Sumatran population alone contains the remnants of at least three separate lineages.

Animals↗
PubMed1995

Constraints on great apes' imitation: model and action selectivity in rehabilitant orangutan (Pongo pygmaeus) imitation.

We discuss selectivity in great ape imitation, on the basis of an observational study of spontaneous imitation in free-ranging rehabilitant orangutans (Pongo pygmaeus). Research on great ape imitation has neglected selectivity, although comparative evidence suggests it may be important. We observed orangutans in central Indonesian Borneo and assessed patterns in the models and actions they spontaneously imitated. The patterns we found resembled those reported in humans. Orangutans preferred models with whom they had positive affective relationships (e.g., important caregiver or older sibling) and actions that reflected their current competence, were receptively familiar, and were relevant to tasks that faced them. Both developmental and individual variability were found. We discuss the probable functions of imitation for great apes and the role of selectivity in directing it. We also make suggestions for more effective elicitation of imitation.

Affect↗
PubMed1993

Imitation in free-ranging rehabilitant orangutans (Pongo pygmaeus).

We made an observational study of spontaneous imitation in orangutans (Pongo pygmaeus). Previous studies may have underestimated great apes' imitative capacities by studying subjects under inhibiting conditions. We used subjects living in enriched environments, namely, rehabilitation. We collected a sample of spontaneous imitations and analyzed the most complex incidents for the likelihood that true imitation, learning new actions by observing rather than by doing, was involved in their acquisition. From 395 hr of observation and other reports on 26 orangutans, we identified 354 incidents of imitation. Of these, 54 complex incidents were difficult to explain by forms of imitation based on associative processes grounded in experimental learning alone; they were, however, congruent with acquisition processes that include true imitation. These findings suggest that orangutans may be capable of true imitation and point to critical eliciting factors.

Animals↗
PubMed1990

Birth spacing patterns in humans and apes.

Comparative studies of birth interval dynamics in wild primates suffer from several problems of analysis and interpretation: (1) the data are always right-censored, (2) sample sizes are usually small, (3) the distribution of birth intervals is expected to be non-normal, (4) early offspring mortality is a confounding variable, and (5) differences in life history (e.g., presence or absence of menopause) can complicate interpretation of the results. A survival analysis designed to minimize these problems is applied to published data on wild chimpanzees and gorillas from Gombe and Virunga Parks, respectively, and to new data on wild orangutans from Tanjung Puting National Park and on a human population, the Gainj of highland Papua New Guinea. According to this analysis, the estimated median birth interval (when the offspring whose birth opens the interval does not die within the interval) is 43.3 +/- 1.0 months for the Gainj, 45.5 +/- 1.2 months for gorillas, 66.6 +/- 1.3 months for chimpanzees, and 92.6 +/- 2.4 months for orangutans.

Animals↗
PubMed1986

A coprological study of parasitism in orangutans (Pongo pygmaeus) in Indonesia.

Fecal specimens from 89 orangutans (36 captive, 34 rehabilitant, and 19 wild) at different locations in Indonesia were examined. Strongyloides spp, Balantidium coli, and strongylid nematodes were the most common infestations detected. A syngamid nematode, Mammomonogamus sp, is reported for the first time in orangutans.

Animals↗