Pongo Abelii Research Articles

Diagnosis of Menopause in a Captive Sumatran Orangutan (Pongo abelii).

Humans were long thought to be the only mammal to experience menopause, the permanent cessation of reproduction followed by a long post-reproductive lifespan. More recently, evidence has been found for the existence of menopause in other long-lived mammals, including chimpanzees and gorillas. However, orangutans, which have the longest interbirth interval of any primate, have rarely been studied in this period of their lives. In this paper, we describe clinical, ultrasound, endocrine, and histological evidence consistent with a natural menopause in a captive, previously fertile, Sumatran orangutan (Pongo abelii), aged approximately 50. Consecutive serum samples showed low levels of estradiol and high levels of follicle-stimulating hormone. Transvaginal ultrasound revealed an atrophic uterus with an antero-posterior diameter of 2.36 cm, an endometrial thickness of 2 mm, and inactive ovaries. Following this female's death from a subdural hematoma, histological examination of the ovaries showed a dense stroma with corpora albicantia, in comparison to the numerous primordial follicles seen in the ovaries of a stillborn infant female orangutan. These multiple lines of evidence suggest that Sumatran orangutans can now be added to the list of mammals which undergo a true menopause, which may ensure that females' final offspring can be reared to independence.

Complete sequencing of ape genomes.

We present haplotype-resolved reference genomes and comparative analyses of six ape species, namely: chimpanzee, bonobo, gorilla, Bornean orangutan, Sumatran orangutan, and siamang. We achieve chromosome-level contiguity with unparalleled sequence accuracy (<1 error in 500,000 base pairs), completely sequencing 215 gapless chromosomes telomere-to-telomere. We resolve challenging regions, such as the major histocompatibility complex and immunoglobulin loci, providing more in-depth evolutionary insights. Comparative analyses, including human, allow us to investigate the evolution and diversity of regions previously uncharacterized or incompletely studied without bias from mapping to the human reference. This includes newly minted gene families within lineage-specific segmental duplications, centromeric DNA, acrocentric chromosomes, and subterminal heterochromatin. This resource should serve as a definitive baseline for all future evolutionary studies of humans and our closest living ape relatives.

Pongo's ecological diversity from dental macrowear analysis

AbstractObjectivesOrangutans are found in tropical rainforests of Borneo (Pongo pygmaeus) and Sumatra (Pongo abelii and Pongo tapanuliensis), and they are primarily considered frugivorous species. However, ecological studies reported differences in feeding behavior between these species. P. pygmaeus spend more time feeding on low‐quality foods, such as bark and tough vegetation than do P. abelii. The aim of this study is to investigate if there is any geographic variation in molar macrowear pattern between the two species.MethodsWe analyzed the macrowear pattern of second mandibular molars of 58 orangutan specimens combining dental topographic measurements (occlusal relief index, percentage of dentine exposure, and percentage of enamel wear) with the occlusal fingerprint analysis method.ResultsThe molar macrowear patterns of P. abelii and P. pygmaeus show no significant differences in most of the variables examined in this study. While P. pygmaeus molars are generally characterized by flatter occlusal morphology with slightly larger crushing and grinding areas than those of P. abelii, these differences are not statistically significant. However, we do observe a more variable wear in P. pygmaeus.ConclusionsSimilarities in molar macrowear patterns between the two species could be linked to overlapping long‐term diets, primarily composed of ripe and pulpy fruits. Dental macrowear is a cumulative process that occurs during the individual's lifetime, and it may be difficult to detect seasonal changes through its examination. Future studies could integrate tooth micro‐ and macrowear data for a better understanding of primate dental ecology.

Phylogenetic differences in the morphology and shape of the central sulcus in great apes and humans: implications for the evolution of motor functions.

The central sulcus divides the primary motor and somatosensory cortices in many anthropoid primate brains. Differences exist in the surface area and depth of the central sulcus along the dorso-ventral plane in great apes and humans compared to other primate species. Within hominid species, there are variations in the depth and aspect of their hand motor area, or knob, within the precentral gyrus. In this study, we used post-image analyses on magnetic resonance images to characterize the central sulcus shape of humans, chimpanzees (Pan troglodytes), gorillas (Gorilla gorilla), and orangutans (Pongo pygmaeus and Pongo abelii). Using these data, we examined the morphological variability of central sulcus in hominids, focusing on the hand region, a significant change in human evolution. We show that the central sulcus shape differs between great ape species, but all show similar variations in the location of their hand knob. However, the prevalence of the knob location along the dorso-ventral plane and lateralization differs between species and the presence of a second ventral motor knob seems to be unique to humans. Humans and orangutans exhibit the most similar and complex central sulcus shapes. However, their similarities may reflect divergent evolutionary processes related to selection for different positional and habitual locomotor functions.

Maternal Behavior in Sumatran Orangutans (Pongo abelii) is Modulated by Mother-Offspring Characteristics and Socioecological Factors

Maternal Behavior in Sumatran Orangutans (Pongo abelii) is Modulated by Mother-Offspring Characteristics and Socioecological Factors

The complete sequence and comparative analysis of ape sex chromosomes

Apes possess two sex chromosomes—the male-specific Y chromosome and the X chromosome, which is present in both males and females. The Y chromosome is crucial for male reproduction, with deletions being linked to infertility1. The X chromosome is vital for reproduction and cognition2. Variation in mating patterns and brain function among apes suggests corresponding differences in their sex chromosomes. However, owing to their repetitive nature and incomplete reference assemblies, ape sex chromosomes have been challenging to study. Here, using the methodology developed for the telomere-to-telomere (T2T) human genome, we produced gapless assemblies of the X and Y chromosomes for five great apes (bonobo (Pan paniscus), chimpanzee (Pan troglodytes), western lowland gorilla (Gorilla gorilla gorilla), Bornean orangutan (Pongo pygmaeus) and Sumatran orangutan (Pongo abelii)) and a lesser ape (the siamang gibbon (Symphalangus syndactylus)), and untangled the intricacies of their evolution. Compared with the X chromosomes, the ape Y chromosomes vary greatly in size and have low alignability and high levels of structural rearrangements—owing to the accumulation of lineage-specific ampliconic regions, palindromes, transposable elements and satellites. Many Y chromosome genes expand in multi-copy families and some evolve under purifying selection. Thus, the Y chromosome exhibits dynamic evolution, whereas the X chromosome is more stable. Mapping short-read sequencing data to these assemblies revealed diversity and selection patterns on sex chromosomes of more than 100 individual great apes. These reference assemblies are expected to inform human evolution and conservation genetics of non-human apes, all of which are endangered species.

Tree architecture model of Sumatran Orangutan Pongo abelii Lesson, 1827 (Mammalia: Primates: Hominidae) nests at Soraya Research Station, Leuser Ecosystem, Indonesia

The relationship between tree architectural models and the nesting behavior of the Sumatran Orangutan Pongo abelii Lesson, 1827 at the Soraya Research Station, Sumatra, Indonesia was determined by examining the preference for particular nest tree architectural models in relation to the frequency of nest occurrence. This investigation included the study of tree architectural models, tree types, nest profiles, vegetation, environmental factors, and geospatial data, collected within a 20 × 1,000 m (2 ha) observational area during a nest survey. A total of 59 orangutan nests were identified across 47 trees, categorized into 31 species and nine varied tree architectural models. Among these, the most prevalent models observed were Cook, Scarrone, and Attims, which exhibit features assumed to enhance orangutan nesting behaviors. Based on the Neu approach to nest qualities, the analytical test findings show a correlation between the preference ratings for nesting trees. Our results are expected to serve as a reference for selecting tree species in rehabilitation or habitat restoration programs and the development of separated forest block corridors as conservation efforts for orangutans.

Active self-treatment of a facial wound with a biologically active plant by a male Sumatran orangutan

Although self-medication in non-human animals is often difficult to document systematically due to the difficulty of predicting its occurrence, there is widespread evidence of such behaviors as whole leaf swallowing, bitter pith chewing, and fur rubbing in African great apes, orangutans, white handed gibbons, and several other species of monkeys in Africa, Central and South America and Madagascar. To the best of our knowledge, there is only one report of active wound treatment in non-human animals, namely in chimpanzees. We observed a male Sumatran orangutan (Pongo abelii) who sustained a facial wound. Three days after the injury he selectively ripped off leaves of a liana with the common name Akar Kuning (Fibraurea tinctoria), chewed on them, and then repeatedly applied the resulting juice onto the facial wound. As a last step, he fully covered the wound with the chewed leaves. Found in tropical forests of Southeast Asia, this and related liana species are known for their analgesic, antipyretic, and diuretic effects and are used in traditional medicine to treat various diseases, such as dysentery, diabetes, and malaria. Previous analyses of plant chemical compounds show the presence of furanoditerpenoids and protoberberine alkaloids, which are known to have antibacterial, anti-inflammatory, anti-fungal, antioxidant, and other biological activities of relevance to wound healing. This possibly innovative behavior presents the first systematically documented case of active wound treatment with a plant species know to contain biologically active substances by a wild animal and provides new insights into the origins of human wound care.

Analysis of land cover changes on the Sumatran Orangutan (Pongo abelii) habitat due to forest fires in Gunung Leuser National Park

Gunung Leuser National Park (GLNP) is home to Indonesia’s native species, the Sumatran orangutan (Pongo abelii). The GLNP in some of its areas has experienced forest degradation, one of which is by land clearing activities by burning. The purpose of this study is to analyze land cover changes due to forest fires in the habitat of Sumatran orangutans in GLNP, Langkat Regency, North Sumatera Province. This study used temporal and spatial analysis of fire hotspot data with land cover. Temporal analysis of land cover changes was conducted between before and after forest and land fires in the study area. There are at least 6,783 ha of forest fires, of which 1,541 ha were habitat distribution areas for Sumatran orangutans. From 2000-2019, 158 hotspots were detected, of which 36 hotspots were in the distribution area of Sumatran orangutan habitat. Land cover in the study area has mostly changed from primary dryland forest to plantations. The primary dryland forest that remained in the study area only 483.51 Ha in 2019 after converting since 2000. Communities around GLNP need to be assisted in the process of ecosystem restoration through a conservation partnership pattern to restore the function of the area, one of which is as a habitat for Sumatran orangutans.

Assessing the Impact of Road Construction on the Sumatran Orangutan (Pongo abelii) Habitat in Pakpak Bharat District from 2003 to 2022

Assessing the Impact of Road Construction on the Sumatran Orangutan (Pongo abelii) Habitat in Pakpak Bharat District from 2003 to 2022

Variation in neophilia in seven primate species.

Neophilia is a measure of individuals' attraction to novelty and is thought to provide important fitness benefits related to the acquisition of information and the ability to solve novel problems. Although neophilia is thought to vary across individuals and species, few studies have made direct comparisons to assess the factors that predict this variation. Here we operationalized neophilia as the probability of interacting with novel objects and compared the response to familiar and novel objects in 53 captive individuals belonging to seven different primate species: chimpanzees (Pan troglodytes), bonobos (Pan paniscus), Sumatran orangutans (Pongo abelii), gorillas (Gorilla gorilla), long-tailed macaques (Macaca fascicularis), tufted capuchin monkeys (Sapajus apella), and Geoffroy's spider monkeys (Ateles geoffroyi). Our results showed that individuals were overall more likely to interact with novel than familiar objects. Moreover, we found no evidence that neophilia varied across individuals depending on their sex, age, and dominance rank. However, macaques were overall less likely to interact with objects (regardless of their novelty), as compared to bonobos, orangutans, gorillas, and capuchin monkeys. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Oxygen isotopes in orangutan teeth reveal recent and ancient climate variation

Studies of climate variation commonly rely on chemical and isotopic changes recorded in sequentially produced growth layers, such as in corals, shells, and tree rings, as well as in accretionary deposits—ice and sediment cores, and speleothems. Oxygen isotopic compositions (δ18O) of tooth enamel are a direct method of reconstructing environmental variation experienced by an individual animal. Here, we utilize long-forming orangutan dentitions (Pongo spp.) to probe recent and ancient rainfall trends on a weekly basis over ~3–11 years per individual. We first demonstrate the lack of any consistent isotopic enrichment effect during exclusive nursing, supporting the use of primate first molar teeth as environmental proxies. Comparisons of δ18O values (n=2016) in twelve molars from six modern Bornean and Sumatran orangutans reveal a high degree of overlap, with more consistent annual and bimodal rainfall patterns in the Sumatran individuals. Comparisons with fossil orangutan δ18O values (n=955 measurements from six molars) reveal similarities between modern and late Pleistocene fossil Sumatran individuals, but differences between modern and late Pleistocene/early Holocene Bornean orangutans. These suggest drier and more open environments with reduced monsoon intensity during this earlier period in northern Borneo, consistent with other Niah Caves studies and long-term speleothem δ18O records in the broader region. This approach can be extended to test hypotheses about the paleoenvironments that early humans encountered in southeast Asia.

Oxygen isotopes in orangutan teeth reveal recent and ancient climate variation.

Studies of climate variation commonly rely on chemical and isotopic changes recorded in sequentially produced growth layers, such as in corals, shells, and tree rings, as well as in accretionary deposits-ice and sediment cores, and speleothems. Oxygen isotopic compositions (δ18O) of tooth enamel are a direct method of reconstructing environmental variation experienced by an individual animal. Here, we utilize long-forming orangutan dentitions (Pongo spp.) to probe recent and ancient rainfall trends on a weekly basis over ~3-11 years per individual. We first demonstrate the lack of any consistent isotopic enrichment effect during exclusive nursing, supporting the use of primate first molar teeth as environmental proxies. Comparisons of δ18O values (n=2016) in twelve molars from six modern Bornean and Sumatran orangutans reveal a high degree of overlap, with more consistent annual and bimodal rainfall patterns in the Sumatran individuals. Comparisons with fossil orangutan δ18O values (n=955 measurements from six molars) reveal similarities between modern and late Pleistocene fossil Sumatran individuals, but differences between modern and late Pleistocene/early Holocene Bornean orangutans. These suggest drier and more open environments with reduced monsoon intensity during this earlier period in northern Borneo, consistent with other Niah Caves studies and long-term speleothem δ18O records in the broader region. This approach can be extended to test hypotheses about the paleoenvironments that early humans encountered in southeast Asia.

Making an Infographic Video on Orangutan Protection as Socialization Media for the Center of Orangutan Protection Sumatra

Socialization activities concerning the importance of orangutan protection carried out by the Center of Orangutan Protection Sumatra in schools and the broader community still use PowerPoint-based media and do not yet have video-based socialization and educational media. This research makes an infographic video about the protection of the Sumatran orangutan and aims to be a socialization medium to obtain information and issues regarding the ecology and habitat of the Sumatran orangutan. This research method uses qualitative and applied research methods with systematic and creative work processes in building visual communication concepts based on video infographics, interviews, observation, and visual literature as the basis for pre-production, production, and post-production of videos. The digital illustrations in the video were worked on using Pain Tool Sai 2, while the video animation used Adobe After Effects 2022. The results of this study use Abelii as the Sumatran orangutan (Pongo Abelii) character, telling about his life under threat of extinction. Video visualization is moving images with transitions containing typography and semi-realistic digital illustrations with two-dimensional animation elements using music and voice acting. The video would be presented at every outreach program conducted by the Center of Orangutan Protection Sumatra and published on YouTube.&#x0D; Keywords: video, infographics, socialization, protection, orangutans

Species Identification of Rehabilitated Critically Endangered Orangutans Through DNA Forensic: Implication for Conservation.

Rehabilitating and releasing orangutans back into the wild is one of the conservation strategies being pursued to conserve orangutans. However, the species determination between Sumatran, Tapanuli, and Bornean orangutans is essential for reintroduction to avoid outbreeding depression, which could lead to DNA hybridisation and increase the probability of recessive characters. Here, we reported on an investigation of three orangutans in which DNA forensic techniques were used to identify the species before release and reintroduction to their habitat. By applying DNA forensic, the orangutan was successfully confirmed with high probabilities (100%) by identifying two orangutan species, Pongo abelii and Pongo pygmaeus wurmbii. Based on ambiguous morphology, we found the possibility of orangutan species being misidentified in rehabilitation. This case report demonstrates the importance of molecular diagnostics to identify the orangutan species. We also provide workflow recommendations from genetic aspect for rehabilitated orangutans. These recommendations will enable decision-makers to consider genetics when assessing future management decisions, which will help ensure that the orangutan species is effectively conserved.

Understanding the welfare requirements of a neurologically and physically divergent captive male Sumatran orangutan (Pongo abelii)

Background Understanding the needs of animals with physical and cognitive impairments is essential for zoos, rehabilitation centres, and other captive contexts. This case study describes the atypical physical and cognitive development of Jiwa, an adult male Sumatran orangutan (Pongo abelii), to evaluate how these differences may impact Jiwa and to explore how cognitive enrichment can be tailored to his skill level. Methods Keeper records from Jiwa’s birth (1999) to February 2022 were scrutinised to identify key developmental milestones, changes in body weight, and deciduous dental emergence. These were compared with expected milestones for wild and captive orangutans. In addition, a probe feeder apparatus was gradually tailored to an appropriate skill level between January and March 2022. Results Many of Jiwa’s developmental milestones were consistent with expected orangutan development, although there were noticeable differences in body weight, dental emergence, locomotion, and cognition. The welfare domains most likely to be negatively impacted by these differences were physical health, expression of agency, and mental wellbeing. After the enrichment device was tailored to an appropriate level of challenge, Jiwa showed marked improvement in engagement and ability to use the device. Conclusions This study helps to inform future case studies of atypical great apes by detailing the physical and cognitive development of an individual orangutan. Although Jiwa’s differences may impact his own wellbeing in some areas, he has largely been able to overcome them. However, this case study highlights the challenges involved in tailoring enrichment apparatuses and resilience interventions for atypical individuals.

Stubby versus stabby: A preliminary analysis of canine microwear in primates: Implication for inferring ingestive behaviors.

Molar and incisor microwear reflect aspects of food choice and ingestive behaviors in living primates and have both been used to infer the same for fossil samples. Canine microwear, however, has received less attention, perhaps because of the prominent role canines play in social display and because they are used as weapons-while outside of a few specialized cases, their involvement in diet related behaviors has not been obvious. Here, we posit that microwear can also provide glimpses into canine tooth use in ingestion. Canines of Sumatran long-tailed macaques (Macaca fascicularis), agile gibbons (Hylobates agilis), lar gibbons (Hylobates lar), Thomas' leaf monkeys (Presbytis thomasi), and orangutans (Pongo abelii), and two African great apes, bonobos (Pan paniscus) and common chimpanzees (Pan troglodytes schweinfurthii), were considered. The labial tips of maxillary canine replicas were scanned using a white-light confocal profiler, and both feature and texture analyses were used to characterize microwear surface patterning. The taxa exhibited significant differences in canine microwear. In some cases, these were consistent with variation in reported anterior tooth use such that, for example, the orangutans, known to use their front teeth extensively in ingestion, had the highest median number of microwear features on their canines, whereas the gibbons, reported to use their front teeth infrequently in food acquisition, had the lowest.

Flanged males have higher reproductive success in a completely wild orangutan population.

Male orangutans (Pongo spp.) exhibit bimaturism, an alternative reproductive tactic, with flanged and unflanged males displaying two distinct morphological and behavioral phenotypes. Flanged males are larger than unflanged males and display secondary sexual characteristics which unflanged males lack. The evolutionary explanation for alternative reproductive tactics in orangutans remains unclear because orangutan paternity studies to date have been from sites with ex-captive orangutans, provisioning via feeding stations and veterinary care, or that lack data on the identity of mothers. Here we demonstrate, using the first long-term paternity data from a site free of these limitations, that alternative reproductive tactics in orangutans are condition-dependent, not frequency-dependent. We found higher reproductive success by flanged males than by unflanged males, a pattern consistent with other Bornean orangutan (Pongo pygmaeus) paternity studies. Previous paternity studies disagree on the degree of male reproductive skew, but we found low reproductive skew among flanged males. We compare our findings and previous paternity studies from both Bornean and Sumatran orangutans (Pongo abelii) to understand why these differences exist, examining the possible roles of species differences, ecology, and human intervention. Additionally, we use long-term behavioral data to demonstrate that while flanged males can displace unflanged males in association with females, flanged males are unable to keep other males from associating with a female, and thus they are unable to completely mate guard females. Our results demonstrate that alternative reproductive tactics in Bornean orangutans are condition-dependent, supporting the understanding that the flanged male morph is indicative of good condition. Despite intense male-male competition and direct sexual coercion by males, female mate choice is effective in determining reproductive outcomes in this population of wild orangutans.

Identification of food type and feeding behavior of sumatran orangutans (Pongo abelii) at the Ketambe Research Station in Gunung Leuser National Park

As an endangered animal, sumatran orangutans ( Pongo abelii ) in Indonesia are declining rapidly. The extinction of food sources that formerly supported their diets is one of the factors that has contributed to this predicament. This paper aims to discover sumatran orangutans’ food types and feeding behaviors at the Ketambe Research Station, Aceh Province, Indonesia. Two orangutans, Chris and Kelly, were the subjects of this study, and their behavior and environment were observed and recorded using the focal animal sampling approach. The study uncovered 29 distinct forms of food (27 plant species and 2 insect species). The type of fruit most consumed by sumatran orangutans ( Pongo abelii ) at the Ketambe Research Station is Ficus racemosa, followed by Ficus obscura, Pandanus sp., and Ficus variegata. The type of leaf most consumed by sumatran orangutans ( Pongo abelii ) is Loides cirrosa, followed by Acacia pennata and Sindapsus hederaceus. Then, their eating behavior patterns cover choosing, holding, taking, and eating the food. The orangutans like eating their meal high up in a tree. As they lead semi-solitary, arboreal lifestyles, preserving the forest ecosystems in which they thrive is crucial.

Understanding others' preferences: A comparison across primate species and human societies.

We investigated children's and non-human great apes' ability to anticipate others' choices from their evident food preferences-regardless of whether these preferences deviate or align with one's own. We assessed children from three culturally-diverse societies (Namibia, Germany, and Samoa; N = 71; age range = 5-11) and four non-human great ape species (chimpanzees (Pan troglodytes), bonobos (Pan paniscus), gorillas (Gorilla gorilla), and orangutans (Pongo abelii); N = 25; age range = 7-29) regarding their choices in a dyadic food-retrieval task. Across conditions, participants' preferences were either aligned (same preference condition) or opposed (opposite preference condition) to those of their competitors. Children across societies altered their choices based on their competitor's preferences, indicating a cross-culturally recurrent capacity to anticipate others' choices relying on preferences-based inferences. In contrast to human children, all non-human great apes chose according to their own preferences but independent of those of their competitors. In sum, these results suggest that the tendency to anticipate others' choices based on their food preferences is cross-culturally robust and, among the great apes, most likely specific to humans.