Acoustic models of orangutan hand-assisted alarm calls

B.d.B. was funded by the European research council starting grant ABACUS project and the Innoviris ‘Brains back to Brussels’ programme. S.A.W. was funded by the Netherlands Organisation for Scientific Research NWO. A.R.L. was funded by the Menken Funds (University of Amsterdam).Orangutans produce alarm calls called kiss-squeaks, which they sometimes modify by putting a hand in front of their mouth. Through theoretical models and observational evidence, we show that using the hand when making a kiss-squeak alters the acoustics of the production in such a way that more formants per kilohertz are produced. Our theoretical models suggest that cylindrical wave propagation is created with the use of the hand and face as they act as a cylindrical extension of the lips. The use of cylindrical wave propagation in animal calls appears to be extremely rare, but is an effective way to lengthen the acoustic system; it causes the number of resonances per kilohertz to increase. This increase is associated with larger animals, and thus using the hand in kiss-squeak production may be effective in exaggerating the size of the producer. Using the hand appears to be a culturally learned behavior, and therefore orangutans may be able to associate the acoustic effect of using the hand with potentially more effective deterrence of predators.Publisher PDFPeer reviewe

A preliminary assessment of using conservation drones for Sumatran orang-utan (Pongo abelii) distribution and density

To conserve biodiversity scientists monitor wildlife populations and their habitats. Current methods have constraints such as the costs of ground or aerial surveys, limited resolution of freely-available satellite images, and expensive high resolution satellite images. Recently researchers started to use unmanned aerial vehicles (aka UAVs or drones) for wildlife and habitat monitoring. Here we tested whether we could detect nests of the critically endangered Sumatran orang-utan on imagery acquired from camera mounted drone to determine distribution and density. Our results show that the distribution of nests compares well between aerial and ground based surveys and that relative density (nest/km) shows a significant correlation between these two survey types. The results also indicate that both methods can be used to detect significant differences in relative density between previously degraded reforested and enriched areas. We conclude that orang-utan nest surveys from drones are a promising survey method to determine distribution and (relative) density of this and perhaps other ape species

Counting crocodiles from the sky: Monitoring the critically endangered gharial (Gavialis gangeticus) population with an Unmanned Aerial Vehicle (UAV).

Technology is rapidly changing the methods in the field of wildlife monitoring. Unmanned aerial vehicle (UAV) is an example of a new technology that allows biologists to take to the air to monitor wildlife. Fixed Wing UAV was used to monitor critically endangered gharial population along 46 km of the Babai River in Bardia National Park. The UAV was flown at an altitude of 80 m along 12 pre-designed missions with a search effort of 2.72 hours of flight time acquired a total of 11,799 images covering an effective surface area of 8.2 km2 of river bank habitat. The images taken from the UAV could differentiate between gharial and muggers. A total count of 33 gharials and 31 muggers with observed density (per km2) of 4.64 and 4.0 for gharial and mugger respectively. Comparison of count data between one-time UAV and multiple conventional visual encounter rate surveys data showed no significant difference in the mean. Basking season and turbidity were important factors for monitoring crocodiles along the river bank habitat. Efficacy of monitoring crocodiles by UAV at the given altitude can be replicated in high priority areas with less operating cost and acquisition of high resolution data

Speech-like rhythm in a voiced and voiceless orangutan call

A.R.L. thanks the Menken Funds of the University of Amsterdam.The evolutionary origins of speech remain obscure. Recently, it was proposed that speech derived from monkey facial signals which exhibit a speech-like rhythm of ∼5 open-close lip cycles per second. In monkeys, these signals may also be vocalized, offering a plausible evolutionary stepping stone towards speech. Three essential predictions remain, however, to be tested to assess this hypothesis' validity; (i) Great apes, our closest relatives, should likewise produce 5Hz-rhythm signals, (ii) speech-like rhythm should involve calls articulatorily similar to consonants and vowels given that speech rhythm is the direct product of stringing together these two basic elements, and (iii) speech-like rhythm should be experience-based. Via cinematic analyses we demonstrate that an ex-entertainment orangutan produces two calls at a speech-like rhythm, coined "clicks" and "faux-speech." Like voiceless consonants, clicks required no vocal fold action, but did involve independent manoeuvring over lips and tongue. In parallel to vowels, faux-speech showed harmonic and formant modulations, implying vocal fold and supralaryngeal action. This rhythm was several times faster than orangutan chewing rates, as observed in monkeys and humans. Critically, this rhythm was seven-fold faster, and contextually distinct, than any other known rhythmic calls described to date in the largest database of the orangutan repertoire ever assembled. The first two predictions advanced by this study are validated and, based on parsimony and exclusion of potential alternative explanations, initial support is given to the third prediction. Irrespectively of the putative origins of these calls and underlying mechanisms, our findings demonstrate irrevocably that great apes are not respiratorily, articulatorilly, or neurologically constrained for the production of consonant- and vowel-like calls at speech rhythm. Orangutan clicks and faux-speech confirm the importance of rhythmic speech antecedents within the primate lineage, and highlight potential articulatory homologies between great ape calls and human consonants and vowels.Peer reviewe

Population-specific use of the same tool-assisted alarm call between two wild orangutan populations (Pongopygmaeus wurmbii) indicates functional arbitrariness

This study was financially supported by Fundação para a Ciência e Tecnologia (SFRH/BD/44437/2008), Wenner-Gren Foundation for Anthropological Research, Dr. J.L. Dobberke voor Vergelijkende Psychologie, Lucie Burgers Foundation for Comparative Behaviour Research, Schure-Beijerinck-Popping Fonds, Ruggles-Gates Fund for Anthropological Scholarship of the Royal Anthropological Institute of Great Britain and Ireland, and Fundação Calouste Gulbenkian. KN and ET were financially supported by Pongo Foundation. Orangutan fieldwork at Cabang Panti was supported by grants to CDK from the 16 National Science Foundation (0936199), the National Geographic Society, the Leakey Foundation and the US Fish and Wildlife Service.Arbitrariness is an elementary feature of human language, yet seldom an object of comparative inquiry. While arbitrary signals for the same function are relatively frequent between animal populations across taxa, the same signal with arbitrary functions is rare and it remains unknown whether, in parallel with human speech, it may involve call production in animals. To investigate this question, we examined a particular orangutan alarm call - the kiss-squeak - and two variants - hand and leaf kiss-squeaks. In Tuanan (Central Kalimantan, Indonesia), the acoustic frequency of unaided kiss-squeaks is negatively related to body size. The modified variants are correlated with perceived threat and are hypothesized to increase the perceived body size of the sender, as the use of a hand or leaves lowers the kiss-squeak's acoustic frequency. We examined the use of these variants in the same context in another orangutan population of the same sub-species and with partially similar habitat at Cabang Panti (West Kalimantan, Indonesia). Identical analyses of data from this site provided similar results for unaided kiss-squeaks but dissimilar results for hand and leaf kiss-squeaks. Unaided kiss-squeaks at Cabang Panti were emitted as commonly and showed the same relationship to body size as in Tuanan. However, at Cabang Panti, hand kiss-squeaks were extremely rare, while leaf-use neither conveyed larger body size nor was related to perceived threat. These findings indicate functional discontinuity between the two sites and therefore imply functional arbitrariness of leaf kiss-squeaks. These results show for the first time the existence of animal signals involving call production with arbitrary function. Our findings are consistent with previous studies arguing that these orangutan call variants are socially learned and reconcile the role of gestures and calls within evolutionary theories based on common ancestry for speech and music.Publisher PDFPeer reviewe

Створення та діяльність УПА в період Другої світової війни в світлі північноамериканської історіографії

У статті здійснено комплексний аналіз північноамериканської історіографії діяльності УПА. Виходячи з методологічних підходів, дослідницьких технік та світоглядних позицій було виокремлено три групи північноамериканських дослідників: емігрантську, діаспорну та американську. Автор зосереджується на детальному аналізі часу створення і чисельності УПА та Волинській трагедії.The article is dedicated to the complex analysis of the North-American historiography of the UPA activity. According to methodological approaches, investigation technique, and world outlook of the authors, the three groups of North-American researchers were singled out: the emigrant, the diaspora and the American one. The author analyzes in detailed the time of creation and number of the UPA troops as well as the Volynian tragedy

Adapting astronomical source detection software to help detect animals in thermal images obtained by unmanned aerial systems

In this paper we describe an unmanned aerial system equipped with a thermal-infrared camera and software pipeline that we have developed to monitor animal populations for conservation purposes. Taking a multi-disciplinary approach to tackle this problem, we use freely available astronomical source detection software and the associated expertise of astronomers, to efficiently and reliably detect humans and animals in aerial thermal-infrared footage. Combining this astronomical detection software with existing machine learning algorithms into a single, automated, end-to-end pipeline, we test the software using aerial video footage taken in a controlled, field-like environment. We demonstrate that the pipeline works reliably and describe how it can be used to estimate the completeness of different observational datasets to objects of a given type as a function of height, observing conditions etc. - a crucial step in converting video footage to scientifically useful information such as the spatial distribution and density of different animal species. Finally, having demonstrated the potential utility of the system, we describe the steps we are taking to adapt the system for work in the field, in particular systematic monitoring of endangered species at National Parks around the world

Distribution and conservation status of the orang-utan (Pongo spp.) on Borneo and Sumatra: how many remain?

In recognition of the fact that orang-utans (Pongo spp.) are severely threatened, a meeting of orang-utan experts and conservationists, representatives of national and regional governmental and non-governmental organizations, and other stakeholders, was convened in Jakarta, Indonesia, in January 2004. Prior to this meeting we surveyed all large areas for which orang-utan population status was unknown. Compilation of all survey data produced a comprehensive picture of orang-utan distribution on both Borneo and Sumatra. These results indicate that in 2004 there were c. 6,500 P. abelii remaining on Sumatra and at least 54,000 P. pygmaeus on Borneo. Extrapolating to 2008 on the basis of forest loss on both islands suggests the estimate for Borneo could be 10% too high but that for Sumatra is probably still relatively accurate because forest loss in orang-utan habitat has been low during the conflict in Aceh, where most P. abelii occur. When those population sizes are compared to known historical sizes it is clear that the Sumatran orang-utan is in rapid decline, and unless extraordinary efforts are made soon, it could become the first great ape species to go extinct. In contrast, our results indicate there are more and larger populations of Bornean orang-utans than previously known. Although these revised estimates for Borneo are encouraging, forest loss and associated loss of orang-utans are occurring at an alarming rate, and suggest that recent reductions of Bornean orang-utan populations have been far more severe than previously supposed. Nevertheless, although orang-utans on both islands are under threat, we highlight some reasons for cautious optimism for their long-term conservatio

Loud calls in male crested macaques, Macaca nigra: a signal of dominance in a tolerant species

Compared to other mammals, sexual signals occur particularly often within the primate order. Nevertheless, little is known so far about the pressures under which these signals evolved. We studied loud calls in wild crested macaques to examine whether these are used as a sexual signal, particularly as a signal of dominance, in this species. Since the structure of loud calls may be influenced by the context in which they are uttered, we tested for contextual differences in call structure. Only males uttered loud calls and analysis of 194 loud calls given by 15 males showed that call structure encoded the caller's identity as well as his social status. Dominance rank was also reflected in the frequency with which males called with alpha males calling most often. The structure of loud calls, however, was not influenced by context. Our findings consolidate the assumption that, in crested macaques, loud calls serve as a signal of dominance, most probably used to prevent contests between males for mates. We herewith provide the first direct evidence for a signal of dominance in a tolerant primate species and discuss why this signal occurs in only one sex

DNA barcoding of nematodes using the MinION

Many nematode species are parasitic and threaten the health of plants and animals, including humans, on a global scale. Advances in DNA sequencing techniques have allowed for the rapid and accurate identification of many organisms including nematodes. However, the steps taken from sample collection in the field to molecular analysis and identification can take many days and depend on access to both immovable equipment and a specialized laboratory. Here, we present a protocol to genetically identify nematodes using 18S SSU rRNA sequencing using the MinION, a portable third generation sequencer, and proof that it is possible to perform all the molecular preparations on a fully portable molecular biology lab – the Bentolab. We show that both parasitic and free-living nematode species (Anisakis simplex, Panagrellus redivivus, Turbatrix aceti, and Caenorhabditis elegans) can be identified with a 96–100% accuracy compared to Sanger sequencing, requiring only 10–15 min of sequencing. This protocol is an essential first step toward genetically identifying nematodes in the field from complex natural environments (such as feces, soil, or marine sediments). This increased accessibility could in turn improve global information of nematode presence and distribution, aiding near-real-time global biomonitoring