Orangutans.

La selva es el hogar de más de la mitad de los animales del mundo desde diminutos insectos a los grandes mamíferos. Se pretende enseñar a los niños el ciclo de vida de l orangutanes y la forma en que interactúan con su entorno, sus hábitos, su estilo de vida y las amenazas a los que se enfrenta por la actuación de los hombres al modificar las condiciones ambientales. La obra contiene un mapa de distribución del hábitat del orangután, glosario y bibliografía.

Feature Versus Spatial Strategies by Orangutans (Pongo abelii) and Human Children (Homo sapiens) in a Cross-Dimensional Task

Despite the fact that photographic stimuli are used across experimental contexts with both human and nonhuman subjects, the nature of individuals' perceptions of these stimuli is still not well understood. In the present experiments, we tested whether three orangutans and 36 human children could use photographic information presented on a computer screen to solve a perceptually corresponding problem in the physical domain. Furthermore, we tested the cues that aided in this process by pitting featural information against spatial position in a series of probe trials. We found that many of the children and one orangutan were successfully able to use the information cross-dimensionally; however, the other two orangutans and almost a quarter of the children failed to acquire the task. Species differences emerged with respect to ease of task acquisition. More striking, however, were the differences in cues that participants used to solve the task: Whereas the orangutan used a spatial strategy, the majority of children used a feature one. Possible reasons for these differences are discussed from both evolutionary and developmental perspectives. The novel results found here underscore the need for further testing in this area to design appropriate experimental paradigms in future comparative research settings.

Rise of the eco warriors

A group of passionate and naïve young people leave their known worlds behind to spend 100 days in the jungles of Borneo. Their mission is to confront one of the great global challenges of our time, saving rainforests and giving hope to endangered orangutans. Their task is enormous and the odds are against them. Jojo, an orphaned baby orangutan, is entrusted in their care and they must find a way to return her to her forest home. To do this, they need to build an orangutan rehabilitation centre and find ways to help the local communities protect their forest. Under the guidance of their mentor Dr Willie Smits, they introduce an innovative satellite monitoring system called Earthwatchers and enlist the help of school students around the world. The system is put to the test when the bulldozers move in and threaten the future of a nearby community living in a traditional longhouse. This is a story about what it takes it be an eco-warrior, an individual willing to step up and take action to avert a global catastrophe taking place before our eyes. The eco-warriors represent a new generation, ready to face what is happening on our planet and willing to do something, no matter how small, to build a more humane and balanced world. For them, every individual matters, every action counts. - Written by Cathy Henkel

The burning season

"Every year deliberately lit fires rage across Indonesia. They destroy pristine rainforest, endanger orangutans and contribute to climate change. A young carbon trading entrepreneur goes in search of a solution." "Dorjee Sun, a young Australian Entrepreneur, believes there's money to be made from protecting rainforests in Indonesia, saving the orangutan from extinction and making a real impact on climate change. Armed with a laptop and a backpack, he sets out across the globe to find investors in his carbon trading scheme. It is a battle against time. Achmadi, the palm oil farmer is ready to set fire to his land to plant more palm oil, and Lone's orangutan centre has reached crisis point with over 600 orangutans rescued from the fires. The Burning Season is an eco-thriller about a young man not afraid to confront the biggest challenge of our time."

A model for tool-use traditions in primates: implications for the coevolution of culture and cognition

Inspired by the demonstration that tool-use variants among wild chimpanzees and orangutans qualify as traditions (or cultures), we developed a formal model to predict the incidence of these acquired specializations among wild primates and to examine the evolution of their underlying abilities. We assumed that the acquisition of the skill by an individual in a social unit is crucially controlled by three main factors, namely probability of innovation, probability of socially biased learning, and the prevailing social conditions (sociability, or number of potential experts at close proximity). The model reconfirms the restriction of customary tool use in wild primates to the most intelligent radiation, great apes; the greater incidence of tool use in more sociable populations of orangutans and chimpanzees; and tendencies toward tool manufacture among the most sociable monkeys. However, it also indicates that sociable gregariousness is far more likely to produce the maintenance of invented skills in a population than solitary life, where the mother is the only accessible expert. We therefore used the model to explore the evolution of the three key parameters. The most likely evolutionary scenario is that where complex skills contribute to fitness, sociability and/or the capacity for socially biased learning increase, whereas innovative abilities (i.e., intelligence) follow indirectly. We suggest that the evolution of high intelligence will often be a byproduct of selection on abilities for socially biased learning that are needed to acquire important skills, and hence that high intelligence should be most common in sociable rather than solitary organisms. Evidence for increased sociability during hominin evolution is consistent with this new hypothesis. (C) 2003 Elsevier Science Ltd. All rights reserved.

Genetic divergence of orangutan subspecies (Pongo pygmaeus)

Microsatellites and mitochondrial DNA sequences were studied for the two subspecies of orangutans (Pongo pygmaeus), which are located in Borneo (P. p, pygmaeus) and Sumatra (P. p. abelii), respectively. Both subspecies possess marked genetic diversity. Ge

Stone tool use in wild bearded capuchin monkeys, Cebus libidinosus. Is it a strategy to overcome food scarcity?

To determine whether tool use varied in relation to food availability in bearded capuchin monkeys, we recorded anvil and stone hammer use in two sympatric wild groups, one of which was provisioned daily, and assessed climatic variables and availability of fruits, invertebrates and palm nuts. Capuchins used tools to crack open encased fruits, mostly palm nuts, throughout the year. Significant differences between wet and dry seasons were found in rainfall, abundance of invertebrates and palm nuts, but not in fruit abundance. Catule nuts were more abundant in the dry season. We tested the predictions of the necessity hypothesis (according to which tool use is maintained by sustenance needs during resource scarcity) and of the opportunity hypothesis (according to which tool use is maintained by repeated exposure to appropriate ecological conditions, such as preferred food resources necessitating the use of tools). Our findings support only the opportunity hypothesis. The rate of tool use was not affected by provisioning, and the monthly rate of tool use was not correlated with the availability of fruits and invertebrates. Conversely, all capuchins cracked food items other than palm nuts (e.g. cashew nuts) when available, and adult males cracked nuts more in the dry season when catule nuts (the most common and exploited nut) are especially abundant. Hence, in our field site capuchins use tools opportunistically. (C) 2012 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Phalangeal curvature and positional behavior in extinct sloth lemurs (Primates, Palaeopropithecidae)

Recent paleontological discoveries in Madagascar document the existence of a diverse clade of palaeopropithecids or “sloth lemurs”: Mesopropithecus (three species), Babakotia (one species), Palaeopropithecus (three species), and Archaeoindris (one species). This mini-radiation of now extinct (“subfossil”) lemurs is most closely related to the living indrids (Indri, Propithecus, and Avahi). Whereas the extant indrids are known for their leaping acrobatics, the palaeopropithecids (except perhaps for the poorly known giant Archaeoindris) exhibit numerous skeletal design features for antipronograde or suspensory positional behaviors (e.g., high intermembral indices and mobile joints). Here we analyze the curvature of the proximal phalanges of the hands and feet. Computed as the included angle (θ), phalangeal curvature develops in response to mechanical use and is known to be correlated in primates with hand and foot function in different habitats; terrestrial species have straighter phalanges than their arboreal counterparts, and highly suspensory forms such as the orangutan possess the most curved phalanges. Sloth lemurs as a group are characterized by very curved proximal phalanges, exceeding those seen in spider monkeys and siamangs, and approaching that of orangutans. Indrids have curvatures roughly half that of sloth lemurs, and the more terrestrial, subfossil Archaeolemur possesses the least curved phalanges of all the indroids. Taken together with many other derived aspects of their postcranial anatomy, phalangeal curvature indicates that the sloth lemurs are one of the most suspensory clades of mammals ever to evolve.

Identification of hepatitis B virus indigenous to chimpanzees

Hepatitis B viruses (HBV) and related viruses, classified in the Hepadnaviridae family, are found in a wide variety of mammals and birds. Although the chimpanzee has been the primary experimental model of HBV infection, this species has not been considered a natural host for the virus. Retrospective analysis of 13 predominantly wild-caught chimpanzees with chronic HBV infection identified a unique chimpanzee HBV strain in 11 animals. Nucleotide and derived amino acid analysis of the complete HBV genome and the gene coding for the hepatitis B surface antigen (S gene) identified sequence patterns that could be used to reliably identify chimpanzee HBV. This analysis indicated that chimpanzee HBV is distinct from known human HBV genotypes and is closely related to HBVs previously isolated from a chimpanzee, gibbons, gorillas, and orangutans.

Self-recognition in primates: phylogeny and the salience of species-typical features.

Self-recognition has been explored in nonlinguistic organisms by recording whether individuals touch a dye-marked area on visually inaccessible parts of their face while looking in a mirror or inspect parts of their body while using the mirror's reflection. Only chimpanzees, gorillas, orangutans, and humans over the age of approximately 2 years consistently evidence self-directed mirror-guided behavior without experimenter training. To evaluate the inferred phylogenetic gap between hominoids and other animals, a modified dye-mark test was conducted with cotton-top tamarins (Saguinus oedipus), a New World monkey species. The white hair on the tamarins' head was color-dyed, thereby significantly altering a visually distinctive species-typical feature. Only individuals with dyed hair and prior mirror exposure touched their head while looking in the mirror. They looked longer in the mirror than controls, and some individuals used the mirror to observe visually inaccessible body parts. Prior failures to pass the mirror test may have been due to methodological problems, rather than to phylogenetic differences in the capacity for self-recognition. Specifically, an individual's sensitivity to experimentally modified parts of its body may depend crucially on the relative saliency of the modified part (e.g., face versus hair). Moreover, and in contrast to previous claims, we suggest that the mirror test may not be sufficient for assessing the concept of self or mental state attribution in nonlinguistic organisms.

Studien über Entwickelungsgeschichte der Thiere.

Vol. 3-5, "Auf grund des nachlasses fortgeführt von A.A.W. Hubrecht ... H. Strahl ... und F. Keibel."

Do dogs (canis familiaris) understand invisible displacement?

Domestic dogs (Canis familiaris) perform above chance on invisible displacement tasks despite showing few other signs of possessing the necessary representational abilities. Four experiments investigated how dogs find an object that has been hidden in 1 of 3 opaque boxes. Dogs passed the task under a variety of control conditions, but only if the device used to displace the object ended up adjacent to the target box after the displacement. These results suggest that the search behavior of dogs was guided by simple associative rules rather than mental representation of the object's past trajectory. In contrast, Experiment 5 found that on the same task, 18- and 24-month-old children showed no disparity between trials in which the displacement device was adjacent or nonadjacent to the target box.

Do chimpanzees (Pan troglodytes) understand single invisible displacement?

Previous research suggests that chimpanzees understand single invisible displacement. However, this Piagetian task may be solvable through the use of simple search strategies rather than through mentally representing the past trajectory of an object. Four control conditions were thus administered to two chimpanzees in order to separate associative search strategies from performance based on mental representation. Strategies involving experimenter cue-use, search at the last or first box visited by the displacement device, and search at boxes adjacent to the displacement device were systematically controlled for. Chimpanzees showed no indications of utilizing these simple strategies, suggesting that their capacity to mentally represent single invisible displacements is comparable to that of 18-24-month-old children.