Sumatran Rhinoceros Research Articles

Analisis Uji Multikolinearitas Variabel Lingkungan Hutan Bakongan-Bengkung, Kawasan Ekosistem Leuser: Implikasi Terhadap Habitat Spesies Kunci

This study aims to analyze the multicollinearity of environmental variables in the Bakongan-Bengkung Forest, part of the Leuser Ecosystem, to understand its implications for the habitat of key species such as Sumatran elephants, Sumatran rhinoceros, Sumatran tigers, and Sumatran orangutans. The research was conducted in August 2023 across an area of 75.912,46 hectares spanning three districts in Aceh. The data utilized includes elevation, slope, river density estimation, Normalized Difference Vegetation Index (NDVI), distance from roads, and annual rainfall, sourced from various geospatial datasets. Data processing was performed using ArcGIS 10.3, Google Earth Engine (GEE), and RStudio 4.2.2. Multicollinearity testing was carried out using Pearson correlation coefficients to identify relationships between environmental variables. The analysis revealed a significant positive correlation between elevation and annual rainfall, with a correlation coefficient of 0,724, indicating a strong linear relationship. This correlation suggests that higher elevations in the area are associated with increased rainfall, likely due to orographic effects. These findings are crucial for conservation planning and habitat management for wildlife. The correlation between elevation and annual rainfall should be considered when developing accurate habitat models for key species in the Bakongan-Bengkung Forest, to ensure effective and sustainable conservation strategies.

Prediction and Analysis of the Global Suitable Habitat of the Oryctes rhinoceros (Linnaeus, 1758) (Coleoptera: Scarabaeidae) Based on the MaxEnt Model.

The Asiatic rhinoceros beetle, Oryctes rhinoceros (Linnaeus, 1758) (Coleoptera: Scarabaeidae), is a destructive invasive species that poses a serious threat to palms, oil palms, and other plants. Defining a suitable area for the distribution of O. rhinoceros is essential for the development of appropriate policies and preventive measures. In this work, the MaxEnt niche model and ArcGIS software were used to predict the potential geographic distribution of O. rhinoceros in the world based on occurrence data and related environmental variables and to speculate on the influence of environmental variables on the distribution of O. rhinoceros. The results showed that the suitable areas of O. rhinoceros beetle were mainly distributed in 30° N-30° S, and the highly suitable areas were concentrated in South Asia, East Asia, Southeast Asia, and northern Oceania. The key environmental variables that determine the distribution location of O. rhinoceros are Precipitation of Wettest Month (bio13), Temperature of July (tmin7), Minimum Temperature of November (tmin11), and Precipitation of September (prec9). The prediction results of the MaxEnt model can reflect the global distribution of O. rhinoceros. This study can provide a theoretical basis for the prevention and control of O. rhinoceros and the development of relevant quarantine measures.

Retracted] Inventory of wild animals along the Bengkunat-Sanggi Road in Bukit Barisan Selatan National Park, Lampung Province, Indonesia

Abstract. Winarno GD, Charles Y, Antonio C. 2024. Inventory of wild animals along the Bengkunat-Sanggi Road in Bukit Barisan Selatan National Park, Lampung Province, Indonesia. Biodiversitas 25: 2917-2924. The quality of the West Sumatra route Bengkunat-Sanggi in Indonesia has significantly improved since 2005, what was originally a dirt road became an asphalt road, leading to an increase in its utilization by various types of vehicles such as motorbikes, sedans, jeeps, buses, and trucks. This condition has an impact on wildlife activities along the road. The sound of vehicles and lights turning on at night can attract animals to move towards the road, which can endanger these animals. On the other hand, lots of vehicles crossing the road can cause animals to run far away because they are disturbed, so it is thought that the animal's movement area will also change. This study aims to explore the effects of road construction on wildlife presence, with a specific emphasis on endangered species like tigers, elephants, and rhinoceroses near the Bukit Barisan Selatan National Park (BBSNP), Indonesia. Camera traps are currently being employed to record animals living in the vicinity of roads, including those that have fallen victim to vehicle collisions. The division of wildlife habitats by roads poses a substantial threat to their survival and functionality. The presence of traffic roads has been linked to an increase in accidents involving animals attempting to cross the road. Some animals appear to be disturbed by the noise generated by vehicles, leading to a reduction in their home range. Initial monitoring results at the onset of road construction indicated a higher presence of threats wild animals, specifically tiger (Panthera tigris subsp. sumatrae Pocock, 1929), Sumatran elephant (Elephas maximus subsp. sumatranus Temminck, 1847) and Sumatran rhino (Dicerorhinus sumatrensis G.Fischer, 1814). To safeguard the wildlife along the Sanggi Bengkunat Road, a comprehensive approach involving all stakeholders and ensuring orderly behavior of drivers while navigating the road is imperative.

The discovery and naming of the Sumatran Rhinoceros (Dicerorhinus sumatrensis) after 1793, with details of the Rhinoceros Sumatricus of Bertuch (1805) and Wilhelm (1808)

There was a considerable gap of 21 years between the illustrated description of a specimen of the Sumatran Rhinoceros (Dicerorhinus sumatrensis) by William Bell in 1793 and the proposal to accept it as a named new species by Gotthelf Fischer in 1814. In the meantime some 17 authors reported the possibility that the animal should be regarded as a new species. Hitherto overlooked, the German writer Friedrich Justin Bertuch used a new name in the caption to a reproduction of Bell’s plate, as Rhinoceros bicornis Sumatricus. This was published in 1805 in a second edition of his “Bilderbuch für Kinder”, a serial magazine aimed at young people. This work has an extremely complex bibliography through many re-issues and translations, which is only partly resolved. The same name in the combination Rhinoceros Sumatricus was included by Gottlieb Tobias Wilhelm in a companion to the “Bilderbuch” available in 1808. The complicated circumstances of Bertuch’s proposal in 1805 and his unusual usage of a trinomen lead to the suggestion that his book might not be consistently binominal, making the name unavailable. The naming by Wilhelm in 1808 is straightforward and correct, hence Rhinoceros sumatricus Wilhelm, 1808 is an available name and a senior objective synonym of Rhinoceros sumatrensis G. Fischer, 1814. The International Code of Zoological Nomenclature allows the suggestion that Wilhelm’s name was a nomen oblitum (forgotten name). The various plates of the rhinoceros found in the “Bilderbuch” by Bertuch and the “Unterhaltungen aus der Naturgeschichte” are figured and explained.

Biodiversity conservation, human-animal interactions, and zootherapy in ecological knowledge of Indonesian Healers.

We examined the entanglement of biodiversity conservation, human-animal interactions, zootherapy, and local beliefs among Sumatran Healers and their local community by completing an ethnography of 43 Indigenous Healers across 8 tribes in Bengkulu Province, Sumatra, Indonesia. Data collection tools were interviews, observations, videos, photographs, and a researcher journal. Of the 43 Healers, 30 used animals and mentioned 62 species. Of the animals identified, the International Union for Conservation of Nature Red List lists 34% (n=21) as endangered, decreasing, or vulnerable, including Sumatran tiger (Panthera tigris sumatrae), Sumatran elephant (Elephas maximus sumatranus), and Sumatran rhinoceros (Dicerorhinus sumatrensis). Of the 30 Healers using animals, 50% (n=15) practiced healing with at least one endangered, decreasing, or vulnerable animal. We defined 3 personas: Healer self-persona, Healer-imposed persona, and community-imposed persona. A persona represented a group's opinions and sentiments related to Healers killing animals for medicinal purposes. Using an iterative data analysis process, we grouped the data across the 3 personas into 5 themes: ease of killing and preparing animals, emotions related to killing animals, animal value, relationship to religion, and Healers are tricksters. The complexity of merging the identities of Healers and the community within an actor-network embodies the relationality of actions, interactions, and feelings among Healers, between Healers and animals, and between Healers and the community. Conservationists should be cognizant of Healers' medicinal use of animals, views of human-animal interactions, and zootherapy from all social and emotional perspectives. The data led to defining Indigenous Healer ecological knowledge components of zootherapy, human-animal interactions, and biodiversity conservation.

Pleistocene Lang Trang fauna in North Vietnam: taxonomic composition and habitats

New data on the taxonomic composition and ecological characteristics of Late Pleistocene vertebrates and invertebrates from the Lang Trang cave in northern Vietnam are presented. Based on the materials collected in progress of the work of the Joint Vietnam - Russia Tropical Science and Technology Research Center in 2020-2022, various representatives of the Stegodon-Ailuropoda Fauna of the second half of the Middle - early Late Pleistocene of Southeast Asia were identified, including primates Gigantopithecus blacki, Pongo sp., Trachypithecus sp., Presbytis sp., Macaca nemestrina, M. cf. fascicularis, M. cf. mulatta, and Macaca sp., carnivorans Panthera tigris, Neofelis nebulosa, and Arctonyx collaris rostratus, a lipotyphlan Chodsigoa hoffmanni, a bat Ia io, rodents Hystrix kiangsenensis, Leopoldamys neilli, and Rattus rattus, proboscideans Stegodon sp. and Elephas maximus, perissodactyls Tapirus indicus, Dicerorhinus sumatrensis, Rhinoceros sondaicus, and Rh. unicornis, artiodactyls Sus scrofa, S. barbatus, Tragulus kanchil, Hydropotes inermis, Muntiacus muntjak, Axis porcinus, Rusa unicolor, Capricornis sumatraensis, Bubalus arnee, and Bos sp., a crocodile Crocodylus sp., a turtle Cuora sp. and an abundant gastropod association, presented by six terrestrial forms, two freshwater species and a coastal-marine species Ellobium aurismidae. Gigantopithecus blacki, Macaca cf. fascicularis, M. cf. mulatta, Neofelis nebulosa, Chodsigoa hoffmanni, Ia io, Leopoldamys neilli, Rattus rattus, Rhinoceros unicornis, Sus barbatus, Tragulus kanchil, Hydropotes inermis, Axis porcinus, crocodiles, turtles, and most of gastropod species were identified for the first time in the Lang Trang Fauna based on these studies. Of particular interest is the finding of the giant ape G. blacki, one of the latest in the fossil record. The habitats of the fauna are characterized as mosaic biotopes with a predominance of wet stations and the participation of mangrove swamps and coastal lowlands; these conditions could have existed in the area of the cave during a major marine transgression of the early Late Pleistocene.

Identifying Appropriate Surrogate for Gunung Leuser Priority Species by Using their Characters and Distributions: A Review

Gunung Leuser National Park (GLNP) priority species is a surrogate species representing four wildlife, Panthera tigris sumatrae, Dicerorhinus sumatrensis, Elephas maximus sumatrensis, and Pongo abelii living within GLNP. GLNP priority species was appointed based on the extinction status, endemicity, population and habitat conditions, threat, and regional representation of wildlife. “GLNP priority species” terminology was considered from flagship species, keystone species, umbrella species, or charismatic species. This literature review aimed to clarify the appropriateness of GLNP priority species to other surrogates by comparing the characters and distributions of GLNP priority species to the definition of surrogate species. This review identified five surrogate species: key-stone species, indicator species, umbrella species, flagship species, and charismatic species. GLNP priority species are appropriate to be GLNP flagship species based on two considerations: (1) the characters of all GLNP priority species which are endemic wildlife of Sumatera and are critically endangered based on the International Union for Conservation of Natures’ status and (2) the condition of the priority species distributions which periodically decreased (elephant and rhino) and are threatened (tiger and orangutan). Besides, tiger and orangutan also can be determined as umbrella species considering their distribution spreads which are extensively covering the GLNP area.

Amplification of The GAPDH Gene from The Urine eDNA of Sumatran Rhino in Sumatran Rhino Sanctuary, Way Kambas National Park

Profiling the genetic character of each individual sumatran rhino is important in order to maintain individual viability and genetic variability of Sumatran rhinos. Non-invasive sampling is needed to minimize the disturbance of individual sumatran rhinos, this is due to the solitary character of sumatran rhinos and tend to be afraid to interact with humans. Until now, non-invasive sampling of sumatran rhinos in Way Kambas National Park (WKNP) has only been done through the source of the puddle. This study aims to amplify the GAPDH gene from sumatran rhino environmental DNA (eDNA) sourced from urine. Urine sampling was carried out on four of the eight sumatran rhino individuals in WKNP. DNA extraction of four sumatran rhino urine samples was carried out with reference to the DNeasy® Blood & tissue kit extraction protocol. Amplification of eDNA extraction results was carried out by polymerase chain reaction (PCR) using GAPDH primers. Visualization of extraction and amplification results from four individual sumatran rhinos at TNWK was tested qualitatively with 1% agarose gel electrophoresis. Electrophoresis results showed positive results after amplification of four individual sumatran rhino urine samples at sizes between 100-200bp. This study successfully amplified the GAPDH gene from four sumatran rhino individuals in WKNP based on qualitative tests. In further conservation efforts, it is necessary to explore eDNA extraction from other potential sources.

Rhinoceros specimens included in anatomical and morphological studies by Professor Alexander J. E. Cave (Perissodactyla: Rhinocerotidae)

Alexander James Edward Cave (1900–2001) was a superb anatomist who extensively improved our knowledge of rhinoceros anatomy and osteology; he also published several studies on the osteology of other groups of mammals and one conservation-focused study about numbers of Ceratotherium cottoni in Uganda. Our contribution contains an identification of the rhinoceros specimens examined by A. J. E. Cave, his complete bibliography related to rhinoceroses, and two recommendations in accord to his legacy. All Cave’s morphological and genetic studies should specify the exact geographic origin of the wild rhinoceroses, if known, and some unambiguous reference numbers in the case of collections and/or captive-based specimens. Cataloguing of extinct and near-extinct extant rhinoceroses in world collections, future preservation of the collection material and its anatomical/morphological documentation for the last remnants of Ceratotherium cottoni, Dicerorhinus sumatrensis, as well as Rhinoceros sondaicus and localized wild-based specimens of Diceros bicornis is highly recommended.

Prolactin enzyme-linked immunosorbent assay for rhinoceroses – Another tool for assessing reproductive function and dysfunction in this taxon

For decades, progesterone and its metabolites have served as the primary biomarkers for monitoring reproductive activity in rhinoceroses, whereas protein hormones have received little attention despite their potential value in understanding reproductive function and dysfunction in this taxon. The goals of this study were to: 1) identify an enzyme-linked immunosorbent assay (ELISA) effective in measuring rhinoceros serum prolactin, 2) generate representative prolactin data in male and female rhinoceroses in diverse reproductive states, and 3) characterize prolactin throughout pregnancy in a white rhinoceros that exhibited mid-gestation lactation. Our results indicated that an equine prolactin ELISA by CUSABIO® is effective in measuring serum prolactin concentrations in white, black and Sumatran rhinoceroses. Preliminary data suggested that prolactin is lowest in males and acyclic females, but also appeared low during post-partum lactation. In contrast, prolactin concentrations were elevated in pregnant females and moderate in sexually mature females experiencing reproductive cyclicity. Prolactin increased following conception and generally continued to rise throughout pregnancy in the one pregnant white rhinoceros profiled herein. Spikes and dips in prolactin and progesterone, respectively, were documented around the time of mid-gestation mammary development and colostrum production in this individual and may provide some clues into the physiological triggers of this newly described aberrant reproductive condition. In conclusion, we have identified a new tool for studying reproductive activity in rhinoceroses, generated preliminary data, and revealed an intriguing relationship between prolactin fluctuations and premature lactation. This work provides the foundation for larger, focused studies on the role of prolactin in this taxon.

Birth of Sumatran rhinoceros (Dicerorhinus sumatrensis) in Way Kambas National Park

The Government of Indonesia (GoI) announced the birth of a Sumatran rhino at the Sumatran Rhino Sanctuary, Way Kambas National Park (SRS), Lampung Province on 24 March 2022. The mother is Rosa, approximately 20 years old and the father is Andatu, who was the first rhino ever born at the Sumatran Rhino Sanctuary. The birth of Rosa’s calf, a female, has increased the number of rhinos at the SRS to eight.

A critical overview on Early Pleistocene Eurasian Stephanorhinus (Mammalia, Rhinocerotidae): Implications for taxonomy and paleobiogeography

Isolated teeth and bones of rhinoceroses are sometimes difficult to identify at specific level because our poor knowledge of the morphological variability of fossil and, often, of extant species. During the past century, several studies have been devoted to highlight morphological and morphometric differences among the fossil Pleistocene species, but only a few of them considered the variability of the extant taxa, in particular Dicerorhinus sumatrensis, to support and interpret their results. Dicerorhinus sumatrensis is the closest extant relative of the Eurasian Stephanorhinus, as recently evidenced by molecular analyses, and it provides useful data to better understand the variability in extinct Pleistocene Eurasian taxa. Taking into account the observations on the extant Sumatran rhinoceros, the validity of some morphological traits, often used for specific attribution in Early Pleistocene fossil rhinoceroses, is revised. Sexual dimorphism and ontogenetic stage drive the development of some important features in Eurasian rhinoceroses and a detailed comparison among crania lead to new considerations on taxonomy, and, therefore, on paleobiogeography and biochronology of the different species.

Potential of cellulolytic fungi isolated from the intestine of Asiatic rhinoceros beetle (Oryctes rhinoceros)

Cellulose is a potential source of fermentable sugars and a promising cost-effective source for biofuel production. This study aimed to obtain potential cellulolytic fungi from the intestine of Asiatic rhinoceros beetle (Oryctes rhinoceros L.). The cellulolytic fungi were isolated using Potato Dextrose Agar (PDA) media using spread plate method. Qualitative and quantitative screening tests were carried out using 1% of CMC (w/v) as a sole carbon source. Twelve isolates were recovered with varying cellulolytic capabilities. The highest cellulolytic activity was obtained from KOr-15J with an index of 1.93 while KOr-23J produced the lowest cellulolytic index (1.01) based on the qualitative screening. The highest cellulase activity assayed using DNS (3,5-Dinitrosalicylic acid) method revealed KOr-21J with an activity of 0.018 U/mL while three isolates (KOr-16J, KOr-19J and KOr-22J) produced the lowest activity (0.003 U/mL). This study provides multiple verifications of the potential ability of cellulolytic fungi and their cellulase activity in the intestine of Asiatic rhinoceros beetle.

Induced pluripotent stem cells and cerebral organoids from the critically endangered Sumatran rhinoceros

Less than 80 Sumatran rhinos (SR, Dicerorhinus sumatrensis) are left on earth. Habitat loss and limited breeding possibilities are the greatest threats to the species and lead to a continuous population decline. To stop the erosion of genetic diversity, reintroduction of genetic material is indispensable. However, as the propagation rate of captive breeding is far too low, innovative technologies have to be developed. Induced pluripotent stem cells (iPSCs) are a powerful tool to fight extinction. They give rise to each cell within the body including gametes and provide a unique modality to preserve genetic material across time. Additionally, they enable studying species-specific developmental processes. Here, we generate iPSCs from the last male Malaysian SR Kertam, who died in2019, and characterize them comprehensively. Differentiation in cells of thethree germ layers and cerebral organoids demonstrate their high quality and great potential for supporting the rescue of this critically endangered species.

Determining the potential distribution of Oryctes monoceros and Oryctes rhinoceros by combining machine-learning with high-dimensional multidisciplinary environmental variables

The African coconut beetle Oryctes monoceros and Asiatic rhinoceros beetle O. rhinoceros have been associated with economic losses to plantations worldwide. Despite the amount of effort put in determining the potential geographic extent of these pests, their environmental suitability maps have not yet been well established. Using MaxEnt model, the potential distribution of the pests has been defined on a global scale. The results show that large areas of the globe, important for production of palms, are suitable for and potentially susceptible to these pests. The main determinants for O. monoceros distribution were; temperature annual range, followed by land cover, and precipitation seasonality. The major determinants for O. rhinoceros were; temperature annual range, followed by precipitation of wettest month, and elevation. The area under the curve values of 0.976 and 0.975, and True skill statistic values of 0.90 and 0.88, were obtained for O. monoceros and O. rhinoceros, respectively. The global simulated areas for O. rhinoceros (1279.00 × 104 km2) were more than that of O. monoceros (610.72 × 104 km2). Our findings inform decision-making and the development of quarantine measures against the two most important pests of palms.

Global potential distribution of Oryctes rhinoceros, as predicted by Boosted Regression Tree model

Climate change is expected to have a significant influence on species range expansion, habitat shifts, and risk of biological invasion due to changes in survival rates, and rapid reproduction. This will tend to affect their geographical distribution and dispersal patterns, thereby threatening agriculture production and food security. Therefore, it is essential to understand the impact of climate change on the range shifts of an invasive species like the Asiatic rhinoceros beetle, Oryctes rhinoceros Linnaeus (Coleoptera: Dynastinae: Scarabaeidae), to inform policy formulation and preventive measures. To achieve this, we used environmental variables and occurrence records of O. rhinoceros to predict the current and future potential distribution of the pest under two representative concentration pathways (RCPs 4.5 and 8.5) for three time periods (2030, 2050, and 2080). We employed Boosted Regression Tree (BRT) and ArcGIS to create risk maps for the pest. The BRT model predicts an expansion of O. rhinoceros outside the current known distribution. The environmental variables which contributed the most to the geographical distribution of the pest were minimum temperature of coldest month (26.81 %), followed by precipitation of wettest month (20.61 %), temperature annual range (11.34 %), mean diurnal range (11.33 %), and elevation (4.49 %). Under the different climate change scenarios, O. rhinoceros will continue to threaten the economically important host plants until 2080. As a result, there will be a need for effective strategies to prevent its spread. Our predictions are reliable and have the potential to estimate the global distribution of the pest, as well as provide suggestions for prompt of O. rhinoceros prevention and management.

Evaluating Sexual Dimorphism in Postcranial Elements of Eurasian Extinct Stephanorhinus etruscus (Falconer, 1868) (Mammalia, Rhinocerotidae)

Sexual dimorphism has been poorly evaluated or investigated in Pleistocene Eurasian Stephanorhinus species, leaving a gap in our knowledge about their morphometric variability. Among the representatives of this genus, S. etruscus is the most abundant species, with several remains collected from Western European localities, allowing us to investigate the presence of sexual dimorphism in the limb bones of this taxon. We considered measurements taken on 45 postcranial variables and three different statistical metrics to identify patterns of bimodality in the dataset. This work represents the first application of sex-combined statistical analysis to a dataset composed of individuals from various European localities. The morphometrical analyses revealed that a relatively weak sexual dimorphism is present in all the considered bones. Larger forelimbs and hindlimbs are interpreted as belonging to adult males of S. etruscus, similarly to what was observed in the modern Sumatran rhino, where males are a little bit larger than females. The recognition of a weak sexual dimorphism in the postcranial bones of S. etruscus increases our understanding of the paleoecology of this extinct taxon. However, only a better study of the morphological and morphometrical variability of the crania of fossil rhinoceroses could deeply contribute to the investigation of the social habits and behavior of these taxa.

Lost mutualisms: Seed dispersal by Sumatran rhinos, the world’s most threatened megafauna

AbstractDiverse assemblages of seed‐dispersing megafauna once existed in Asian rainforests, but are now almost solely represented by elephants. Asia's rhinos persist in remnant, ecologically extinct populations and the most threatened of these is the Sumatran rhino, Dicerorhinus sumatrensis. To understand the seed dispersal role of Sumatran rhinos, we consolidated information on fruit consumption, seed dispersal, and fruit traits from a 2‐month field study (Sumatra), local ecological knowledge (Peninsular Malaysia), and published and unpublished accounts. We evaluated differences between the taxa and traits of fruits dispersed by rhinos and elephants, and identified other dispersers of megafaunal‐syndrome fruits that were rhino‐dispersed. At least 79 plant species were dispersed by rhinos: overstorey plants (trees and climbers; 78% of species) had large, usually “mammal‐colored,” fruits and seeds, and were mainly drupes and berries; 61% of these were megafaunal‐syndrome fruits (>4 cm wide). Understorey plants (herbs, shrubs, and small trees) had small, often capsular, fruits and seeds that are potentially dispersed following the “foliage‐is‐the‐fruit” hypothesis. Rhinos were the only known disperser for 35% of the megafaunal‐fruit genera. The highest dispersal overlap shown was with elephants: fruits dispersed by rhinos tended to be capsular and were smaller than fruits dispersed by both elephants and rhinos. Given these findings and the different foraging and ranging behavior of Sumatran rhinos and elephants, we suggest that these megafauna had important differences in their seed dispersal roles. Asian rainforests have, therefore, lost an important seed dispersal mutualist. Conservation efforts should aim to protect and restore the ecological function of these unique creatures.Abstract in Indonesian is available with online material.

Rhinoceros serum labile plasma iron and associated redox potential: interspecific variation, sex bias and iron overload disorder disconnect.

A consequence of the poaching crisis is that managed rhinoceros populations are increasingly important for species conservation. However, black rhinoceroses (BR; Diceros bicornis) and Sumatran rhinoceroses (SR; Dicerorhinus Sumatrensis) in human care often store excessive iron in organ tissues, a condition termed iron overload disorder (IOD). IOD research is impeded by the challenge of accurately monitoring body iron load in living rhinoceroses. The goals of this study were to (i) determine if labile plasma iron (LPI) is an accurate IOD biomarker and (ii) identify factors associated with iron-independent serum oxidative reduction potential (ORP). Serum (106 samples) from SRs (n = 8), BRs (n = 28), white rhinoceros (n = 24) and greater one-horned rhinoceros (GOH; n = 16) was analysed for LPI. Samples from all four species tested positive for LPI, and a higher proportion of GOH rhinoceros samples were LPI positive compared with those of the other three species (P < 0.05). In SRs, the only LPI-positive samples were those from individuals clinically ill with IOD, but samples from outwardly healthy individuals of the other three species were LPI positive. Serum ORP was lower in SRs compared with that in the other three species (P < 0.001), and iron chelation only reduced ORP in the GOH species (P < 0.01; ~5%). Serum ORP sex bias was revealed in three species with males exhibiting higher ORP than females (P < 0.001), the exception being the SR in which ORP was low for both sexes. ORP was not associated with age or serum iron concentrations (P ≥ 0.05), but was positively correlated with ferritin (P < 0.01). The disconnect between LPI and IOD was unanticipated, and LPI cannot be recommended as a biomarker of advanced rhino IOD. However, data provide valuable insight into the complex puzzle of rhinoceros IOD.

Induced Pluripotent Stem Cells and Cerebral Organoids From the Critically Endangered Sumatran Rhinoceros

Induced Pluripotent Stem Cells and Cerebral Organoids From the Critically Endangered Sumatran Rhinoceros