The behavioral ecology and conservation of the orangutan (Pongo pygmaeus): A tale of two islands

Delgado, Roberto A.; Schaik, Carel P. van

doi:10.1002/1520-6505(2000)9:5<201::aid-evan2>3.0.co;2-y

Cited by 263 publications

(166 citation statements)

References 94 publications

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“…The extinction of the giant pangolin soon after the presumed arrival date was attributed above to the loss of open habitats, but a slow-moving, 2 m long mammal whose only defence was to roll up must also have been exceptionally vulnerable to hunting. A similar argument can be made for the slowmoving, slow-breeding orangutans, which ranged widely over tropical East Asia in the late Pleistocene, from southern China to Java, but were confined to the sparsely populated everwet rainforests of Borneo and Sumatra by historical times (Delgado and van Schaik 2000). The giant panda and the New Guinea megafaunal marsupials may also have been particularly vulnerable to hunters for similar reasons, but there seems to be no obvious pattern to most other pre-recent extinctions.…”

Section: Terra Australis 32mentioning

confidence: 67%

Altered Ecologies: Fire, climate and human influence on terrestrial landscapes: Terra Australis 32

Haberle¹,

Stevenson²,

Prebble³

2010

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terra australis 32Terra Australis reports the results of archaeological and related research within the south and east of Asia, though mainly Australia, New Guinea and island Melanesia -lands that remained terra australis incognita to generations of prehistorians. Its subject is the settlement of the diverse environments in this isolated quarter of the globe by peoples who have maintained their discrete and traditional ways of life into the recent recorded or remembered past and at times into the observable present.Since the beginning of the series, the basic colour on the spine and cover has distinguished the regional distribution of topics as follows: ochre for Australia, green for New Guinea, red for South-East Asia and blue for the Pacific Islands. From 2001, issues with a gold spine will include conference proceedings, edited papers and monographs which in topic or desired format do not fit easily within the original arrangements. All volumes are numbered within the same series. Copyright of the text remains with the contributors/authors, 2009. This book is copyright in all countries subscribing to the Berne convention. Apart from any fair dealing for the purpose of private study, research, criticism or review, as permitted under the Copyright Act, no part may be reproduced by any process without written permission. Inquiries should be made to the publisher. Among saltbush greyer than seaweed we boardwalk the yeasting waves of the old golden-perch pond. List of volumes in Terra AustralisRabbit dung dots a lake bottom dry since their coming -only once, last century, after seven inches of rain a farmer had to rescue his sheep by boat.The roo bounces down-slope, a brown branch crackling.The professor's eye, noting the local runoff and what the westerlies do, observes seas that rush in and out of a continent's middle, salt lakes spreading and emptying, hills pimpling up and down with cartoon-like speed, or gullying themselves into extinction, rainforests and deserts zipping back and forth like Tom and Jerry. A human mouse plague swiftly swarms, perhaps soon gone.Impermanent planet. Impermanent surface. All under air and water. The lunette is a wave, a dumper of sand, a collapsing tower in the mad rabbit years when its top blew off and old bones winked through, with a vault's worth of fine stone cores.Once so simply mislaid in sand, now so obligingly sluiced out to the un-subincised world that smiles at stone knives. terra australis 32Altered Ecologies: Fire, climate and human influence on terrestrial landscapes v You might as well offer your table knife to a carpenter.Cane grass and the Dreamtime's stone fight the eroding rivulets together. In today's rare downpour each lost core, or blunted scraper crowns some tiny eroding hillock, plops its anchor in the dissolving silts.The bettong whose skin took off the stone tool's edge has vanished -sacrifice to future fertility.Through the softening soil Homo sapiens's skeleton bumps up like a carp's back.Waits for the wind to shave it off in pieces.A D-section and a ti...

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Section: Terra Australis 32mentioning

confidence: 67%

Altered Ecologies: Fire, climate and human influence on terrestrial landscapes: Terra Australis 32

Haberle¹,

Stevenson²,

Prebble³

2010

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“…The orangutans' results, on the other hand, are more surprising as they are a semisolitary species, and presumably their social cognition might differ from that of the other more social apes. However, some researchers (Delgado & van Schaik, 2000;van Schaik, 2003) have argued that mean party size in orangutans remains small only because of the high costs of feeding competition. If the habitat is productive enough, they form parties that are comparable with the fission-fusion societies of chimpanzees.…”

Section: Discussionmentioning

confidence: 99%

“…If the habitat is productive enough, they form parties that are comparable with the fission-fusion societies of chimpanzees. Moreover, it is suggested that the main benefits of grouping in orangutans are social (Delgado & van Schaik, 2000;van Schaik, 2003).…”

Section: Discussionmentioning

confidence: 99%

“…It is interesting that they only detected two incidences of gaze following out of more than 200 gaze episodes toward conspecifics. Because orangutans live a semisolitary existence (Delgado & van Schaik, 2000), one might expect that visual communication does not play such a big role as for the other great ape species. A similar lack of information exists for bonobos (Pan paniscus).…”

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confidence: 99%

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All Great Ape Species Follow Gaze to Distant Locations and Around Barriers.

Bräuer

Call

Tomasello

2005

Journal of Comparative Psychology

252

199

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Following the gaze direction of conspecifics is an adaptive skill that enables individuals to obtain useful information about the location of food, predators, and group mates. In the current study, the authors compared the gaze-following skills of all 4 great ape species. In the 1st experiment, a human either looked to the ceiling or looked straight ahead. Individuals from all species reliably followed the human's gaze direction and sometimes even checked back when they found no target. In a 2nd experiment, the human looked behind some kind of barrier. Results showed that individuals from all species reliably put themselves in places from which they could see what the experimenter was looking at behind the barrier. These results support the hypothesis that great apes do not just orient to a target that another is oriented to, but they actually attempt to take the visual perspective of the other.

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“…snakes, clouded leopards, tigers, humans) or other orang-utans upon sight, at times accompanied by display behaviour and most likely to deter the potential predator (Rijksen 1978;Hardus et al 2009). Because orang-utans are semi-solitary animals living in fission -fusion societies (Delgado & Van Schaik 2000), it often takes hours before conspecifics are attracted to the kiss squeaks (Van Noordwijk & Van Schaik 2009), so its most likely function is to send a signal to the predator or approaching orang-utan and not to attract other conspecifics.…”

Section: Introductionmentioning

confidence: 99%

Tool use in wild orang-utans modifies sound production: a functionally deceptive innovation?

et al. 2009

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Culture has long been assumed to be uniquely human but recent studies, in particular on great apes, have suggested that cultures also occur in non-human primates. The most apparent cultural behaviours in great apes involve tools in the subsistence context where they are clearly functional to obtain valued food. On the other hand, tool-use to modify acoustic communication has been reported only once and its function has not been investigated. Thus, the question whether this is an adaptive behaviour remains open, even though evidence indicates that it is socially transmitted (i.e. cultural). Here we report on wild orang-utans using tools to modulate the maximum frequency of one of their sounds, the kiss squeak, emitted in distress. In this variant, orang-utans strip leaves off a twig and hold them to their mouth while producing a kiss squeak. Using leaves as a tool lowers the frequency of the call compared to a kiss squeak without leaves or with only a hand to the mouth. If the lowering of the maximum frequency functions in orang-utans as it does in other animals, two predictions follow: (i) kiss squeak frequency is related to body size and (ii) the use of leaves will occur in situations of most acute danger. Supporting these predictions, kiss squeaks without tools decreased with body size and kiss squeaks with leaves were only emitted by highly distressed individuals. Moreover, we found indications that the calls were under volitional control. This finding is significant for at least two reasons. First, although few animal species are known to deceptively lower the maximum frequency of their calls to exaggerate their perceived size to the listener (e.g. vocal tract elongation in male deer) it has never been reported that animals may use tools to achieve this, or that they are primates. Second, it shows that the orang-utan culture extends into the communicative domain, thus challenging the traditional assumption that primate calling behaviour is overall purely emotional.

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The behavioral ecology and conservation of the orangutan (Pongo pygmaeus): A tale of two islands

Cited by 263 publications

References 94 publications

Altered Ecologies: Fire, climate and human influence on terrestrial landscapes: Terra Australis 32

Altered Ecologies: Fire, climate and human influence on terrestrial landscapes: Terra Australis 32

All Great Ape Species Follow Gaze to Distant Locations and Around Barriers.

Tool use in wild orang-utans modifies sound production: a functionally deceptive innovation?

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