Diceros Research Articles

Sperm collection in rhinoceros via urethral catheterization

Assisted reproductive technologies are playing an ever-increasing role in the management of ex situ rhinoceros populations. Traditionally, sperm collection in rhinos is conducted via electroejaculation (EEJ) or gamete rescue. Sperm collection via urethral catheterization (UC) is gaining popularity in wildlife reproductive sciences as it requires less specialized equipment, is faster, and less stimulatory than EEJ. This study investigated the use of UC to collect sperm from Southern white (Ceratotherium simum simum; n = 3) and Eastern black (Diceros bicornis michaeli; n = 6) rhinoceros as an alternative or complementary to collection via EEJ. UC samples (n = 14) exhibited high sperm concentration (1.6 ± 0.49 ×109 sperm/mL) and low volume (0.98 ± 0.26 mL). Samples obtained via EEJ (n = 11) were of moderate sperm concentration (0.14 ± 0.05 ×109 sperm/mL) and high volume (30.6 ± 7.2 mL). UC samples were processed for cryopreservation in OptiXcell extender. Motility of UC sperm decreased post-thaw (56 ± 2.4%) over pre-freeze (77.1 ± 3.2%; P < 0.05), with longevity data consistent to prior results published for sperm collected via EEJ. These results suggest sperm quality and cryo-survival are not impacted by the collection method. Since EEJ was conducted after UC, sperm parameters could not be compared between the two methods. Results indicate that UC is a viable alternative to EEJ for sperm collection in rhinoceros.

Physiological stress in eastern black rhinoceros (Diceros bicornis michaeli) as influenced by their density, climatological variables and sexes

AbstractIt is important to understand the physiological stressors in animals especially for threatened species or intensively managed to improve their conservation and optimise their reproduction. We sought to understand changes in stress hormones (faecal glucocorticoid metabolites) in black rhinoceros (Diceros bicornis michaeli) in relation to population density and sex (intrinsic factors) and plant minerals, rainfall and land surface temperature (extrinsic factors). We used non‐invasive faecal sampling techniques on animals of known sex, age and dominance in seven populations of contrasting population densities over 1 year. We measured variability in faecal corticosterone metabolites through radioimmunoassay and related them to population density, sex and faecal calcium, phosphorus, copper, zinc and potassium as characteristic of plant minerals, rainfall and temperature. We used linear mixed models (LMM) to analyse the data. We did not detect a significant relationship between physiological stress parameters and population density. However, we have indications that stress levels increased as rainfall and temperature increased and were correlated negatively and positively with concentration of faecal phosphorus and copper respectively; we found higher stress levels in females than in males. These results suggest that both intrinsic and extrinsic factors explain the variation in physiological stress observed in black rhinoceros.

21 Investigating the role of serum progesterone, estrogen, and testosterone in cyclic and acyclic black rhinos

21 Investigating the role of serum progesterone, estrogen, and testosterone in cyclic and acyclic black rhinos

Bringing the Black rhino back: Key factors for reintroduction success

Evaluating reintroduction success is fundamental to wildlife management and conservation. Movement affects animal fitness and survival and is the first response of reintroduced animals, making it an excellent indicator of reintroduction success. However, there is limited information on the early post-release movement of reintroduced animals. Here, we addressed this important issue by studying the post-release behaviour of the critically endangered black rhinoceros, Diceros bicornis minor, reintroduced to the Gonarezhou National Park, Zimbabwe, in 2021. We used daytime sighting data collected from 21 rhinoceros for 1.5 years to investigate survival and reproduction, movement patterns and habitat selection after release. We examine how sex, age and different release sites affect the short-term movement behaviour and habitat selection of black rhinos. Rhinos showed progressive and consistent changes in movement patterns and habitat selection, shifting from large-scale movements during the early stages of release to smaller-scale movements after home ranges were established. We found that rhinos released in the large area had larger activity areas with less overlap between individuals and moved further away from the release site (less fidelity to the release site) than the individuals released in the smaller area. These findings confirm the great capacity of black rhinos to adapt to the environment, occupying large ranges when given the opportunity, but populations with smaller ranges can also be viable. Based on our study and a literature review, we stress the importance of long-term monitoring and believe that reserve size, rhino density, fencing, food and water availability, familiarity between conspecifics and human disturbance are key factors in the successful establishment of a rhino population that should be considered in future reintroductions. Finally, the high survival and birth rates in the first 1.5 years after reintroduction, together with most rhinos having established their home range, suggest a successful reintroduction in the short term.

Parturition and Neonatal Parameters of Three Species of Rhinoceros under Managed Care in the United States

Rhinoceros species range from near threatened to critically endangered due to habitat loss and poaching. A sustainable ex situ breeding population is critically important to maintain genetic diversity and help ensure the survival of the species; however, not all populations under human care are self-sustaining. While rhinoceros reproductive physiology and pathology have been well studied, there is still a paucity of information describing the normal parameters of parturition and neonatal landmarks. Using video recordings, medical records, and keeper logs, we reviewed and compared data regarding the parturition of three rhinoceros species (black rhinoceros (BR) (Diceros bicornis), n = 4; greater one-horned rhinoceros (GOHR) (Rhinoceros unicornis), n = 21; and southern white rhinoceros (SWR) (Ceratotherium simum simum), n = 22) managed under human care in the United States. Using equine parameters as a model for comparison, we compiled the following data: the signs of impending parturition, durations of the parturition phases, calving presentation, frequency of dystocia or stillbirth, and time from birth to neonatal landmarks. Data from 47 births, including 26 videos, were examined. The durations of parturition phases I, II, and III had median lengths of 153 min (n = 18), 28 min (n = 21), and 205 min (n = 15), respectively. Anterior presentation of the calf was observed in 59% births, whereas posterior presentation occurred in 41% births. Posterior calving presentation was associated with a longer phase II of parturition (p = 0.04), although more data are needed to determine whether the posterior presentation of the calf carries a higher risk for stillbirth. Most (83%) stillbirths occurred in GOHR, indicating that this species might be at a higher risk for stillbirth compared to SWR (17%) (p = 0.07). The median time from birth to the calf standing was longer in the GOHR (64 min) compared to the SWR (30 min) (p = 0.02). Detailed descriptions of the parturition parameters and neonatal landmarks in rhinoceros will aid facilities with rhinoceros breeding programs to recognize abnormalities in the parturient or post-partum periods and guide indications for veterinary intervention.

Survival of Young Black and White Rhinoceroses in Relation to Rainfall

Survival of Young Black and White Rhinoceroses in Relation to Rainfall

In vitro fertilization program in white rhinoceros.

To save endangered rhinoceros species, assisted reproductive technologies are warranted. We here report in vitro blastocyst generation of the Near-Threatened Southern white rhinoceros and, for the first time, also of the technically Extinct Northern white rhinoceros. The Anthropocene is marked by a dramatic biodiversity decline, particularly affecting the family Rhinocerotidae. Three of five extant species are listed as Critically Endangered (Sumatran, Javan, black rhinoceros), one as Vulnerable (Indian rhinoceros), and only one white rhino (WR) subspecies, the Southern white rhinoceros (SWR), after more than a century of successful protection is currently classified as Near Threatened by the IUCN, while numbers again are declining. Conversely, in 2008, the SWR's northern counterpart and second WR subspecies, the Northern white rhinoceros (NWR), was declared extinct in the wild. Safeguarding these vanishing keystone species urgently requires new reproductive strategies. We here assess one such strategy, the novel in vitro fertilization program in SWR and - for the first-time NWR - regarding health effects, donor-related, and procedural factors. Over the past 8 years, we performed 65 procedures in 22 white rhinoceros females (20 SWR and 2 NWR) comprising hormonal ovarian stimulation, ovum pick-up (OPU), in vitro oocyte maturation, fertilization, embryo culture, and blastocyst cryopreservation, at an efficiency of 1.0 ± 1.3 blastocysts per OPU, generating 22 NWR, 19 SWR and 10 SWR/NWR hybrid blastocysts for the future generation of live offspring.

Metabolomic profiling implicates mitochondrial and immune dysfunction in disease syndromes of the critically endangered black rhinoceros (Diceros bicornis)

The critically endangered black rhinoceros (Diceros bicornis; black rhino) experiences extinction threats from poaching in-situ. The ex-situ population, which serves as a genetic reservoir against impending extinction threats, experiences its own threats to survival related to several disease syndromes not typically observed among their wild counterparts. We performed an untargeted metabolomic analysis of serum from 30 ex-situ housed black rhinos (Eastern black rhino, EBR, n = 14 animals; Southern black rhino, SBR, n = 16 animals) and analyzed differences in metabolite profiles between subspecies, sex, and health status (healthy n = 13 vs. diseased n = 14). Of the 636 metabolites detected, several were differentially (fold change > 1.5; p < 0.05) expressed between EBR vs. SBR (40 metabolites), female vs. male (36 metabolites), and healthy vs. diseased (22 metabolites). Results suggest dysregulation of propanoate, amino acid metabolism, and bile acid biosynthesis in the subspecies and sex comparisons. Assessment of healthy versus diseased rhinos indicates involvement of arachidonic acid metabolism, bile acid biosynthesis, and the pentose phosphate pathway in animals exhibiting inflammatory disease syndromes. This study represents the first systematic characterization of the circulating serum metabolome in the black rhinoceros. Findings further implicate mitochondrial and immune dysfunction as key contributors for the diverse disease syndromes reported in ex-situ managed black rhinos.

Highlight: Genomic Insights into the Past and Future of the Black Rhinoceros

Highlight: Genomic Insights into the Past and Future of the Black Rhinoceros

Breast Milk Oligosaccharides Contain Immunomodulatory Glucuronic Acid and LacdiNAc

Breast milk is abundant with functionalized milk oligosaccharides (MOs) to nourish and protect the neonate. Yet we lack a comprehensive understanding of the repertoire and evolution of MOs across Mammalia. We report ∼400 MO-species associations (>100 novel structures) from milk glycomics of nine mostly understudied species: alpaca, beluga whale, black rhinoceros, bottlenose dolphin, impala, L'Hoest's monkey, pygmy hippopotamus, domestic sheep, and striped dolphin. This revealed the hitherto unknown existence of the LacdiNAc motif (GalNAcβ1-4GlcNAc) in MOs of all species except alpaca, sheep, and striped dolphin, indicating the widespread occurrence of this potentially antimicrobial motif in MOs. We also characterize glucuronic acid-containing MOs in the milk of impala, dolphins, sheep, and rhinoceros, previously only reported in cows. We demonstrate that these GlcA-MOs exhibit potent immunomodulatory effects. Our study extends the number of known MOs by >15%. Combined with >1900 curated MO-species associations, we characterize MO motif distributions, presenting an exhaustive overview of MO biodiversity.

Historic Sampling of a Vanishing Beast: Population Structure and Diversity in the Black Rhinoceros.

The black rhinoceros (Diceros bicornis L.) is a critically endangered species historically distributed across sub-Saharan Africa. Hunting and habitat disturbance have diminished both its numbers and distribution since the 19th century, but a poaching crisis in the late 20th century drove them to the brink of extinction. Genetic and genomic assessments can greatly increase our knowledge of the species and inform management strategies. However, when a species has been severely reduced, with the extirpation and artificial admixture of several populations, it is extremely challenging to obtain an accurate understanding of historic population structure and evolutionary history from extant samples. Therefore, we generated and analyzed whole genomes from 63 black rhinoceros museum specimens collected between 1775 and 1981. Results showed that the black rhinoceros could be genetically structured into six major historic populations (Central Africa, East Africa, Northwestern Africa, Northeastern Africa, Ruvuma, and Southern Africa) within which were nested four further subpopulations (Maasailand, southwestern, eastern rift, and northern rift), largely mirroring geography, with a punctuated north-south cline. However, we detected varying degrees of admixture among groups and found that several geographical barriers, most prominently the Zambezi River, drove population discontinuities. Genomic diversity was high in the middle of the range and decayed toward the periphery. This comprehensive historic portrait also allowed us to ascertain the ancestry of 20 resequenced genomes from extant populations. Lastly, using insights gained from this unique temporal data set, we suggest management strategies, some of which require urgent implementation, for the conservation of the remaining black rhinoceros diversity.

Probabilistic assessment of the risk of black rhinoceros (Diceros bicornis) species extinction

AbstractThe black rhinoceros (Diceros bicornis), distinguished by its distinctive horned snout and imposing size, stands perilously close to the precipice of extinction. The survival of this majestic species is threatened by a combination of factors, necessitating urgent scientific inquiry into the underlying causes. In this research article, a nonlinear stochastic Ricker model is employed to investigate the challenges faced by the population of black rhinoceros. By integrating innovative mathematical approaches with ecological understanding, the aim is to unravel the intricate dynamics contributing to the endangered status of the black rhino. The critical role of habitat loss and illicit poaching activities in driving the decline of this remarkable species is highlighted by the analysis. These findings emphasise the need for immediate and decisive action to protect the black rhinoceros and mitigate the risk of its extinction. It is imperative that comprehensive conservation efforts be implemented to ensure the long‐term survival of the black rhinoceros and preserve its invaluable place within the ecosystem.

Mitochondrial DNA diversity of the eastern black rhinoceros (Diceros bicornis michaeli) in Tanzania: implications for future conservation

There has been a drastic decline in the number of eastern black rhinoceros (Diceros bicornis michaeli) across Africa, leaving individuals restricted to small, isolated populations that are vulnerable to extinction. Focusing on highly threatened populations in Tanzania, this study investigated the genetic impacts of past management interventions on mitochondrial control region diversity in extant subpopulations, assessed whether there has been evidence of dispersal of females between populations based on haplotype sharing, and related current haplotype diversity to historical patterns. Across extant subpopulations in Tanzania, six maternal haplotypes were identified, with an overall haplotype diversity of h = 0.72 but lower overall nucleotide diversity within populations (π = 0.017) compared to historical populations (π = 0.021). Translocated populations did not share haplotypes with native populations, even though all haplotypes from translocated individuals had been found among historic samples from Kenya. This suggests that translocations have been successful at restoring previous diversity to the region but that the current Intensive Protection Zone (IPZ) management practices have restricted the movement of females between subpopulations. Extant haplotypes were distributed among three East African haplogroups described in previous studies, suggesting that multiple lineages have been preserved despite the loss of historical haplotypes. Our recommendation is to enhance the utilisation of previous translocations by enabling the natural movements of individuals between subpopulations. Such a change in management strategy could be less costly both economically and in terms of animal welfare than the alternative of using genetic data to target specific animals for translocation in order to supplement diversity.

Finance and biodiversity conservation: insights from rhinoceros conservation and the first wildlife conservation bond

AbstractThe Rhino Bond is the first financial instrument dedicated to protecting a species. The Bond allows investors to invest in the conservation of the black rhinoceros Diceros bicornis, with the amount of money returned by the investment depending on whether rhinoceros numbers increase (and by how much). In this paper we focus on how the Bond was brought into being. We draw on an analysis of organizational reports along with data collected from interviews with key informants to investigate the roles of the various stakeholders in the Bond, how species and sites were selected, the motivations and experiences of the stakeholders and the involvement of stakeholders in decision-making. We found that although conservation actors are attracted by the potential for new funding, they have experienced challenges navigating complex financial instruments. The needs of financial actors often dictated decision-making, with implications for the species and sites chosen for the Bond. As profits are tied to an increase in population size of a specific species (which needs to be monitored), the instrument has favoured large and easily counted species and populations. Only some sites were able to meet the stringent conditions of financial instruments, including metrics on financial sustainability. We argue that the dominance of financial principles and motives means that not all species or sites will be viable candidates for investment and that conservation finance should not be seen as a panacea.

Ciliates from the intestine of zoo-kept black rhinoceros, with immunofluorescence microscopic and molecular phylogenetic investigation of Rhinozeta rhinozeta (Litostomatea)

The study of endobiotic ciliates from the intestines of various zoo mammals is important for revealing the influence of various factors on endobiont communities. In this paper we describe the species diversity of endobiotic ciliates from the faeces of the eastern black rhinoceros Diceros bicornis michaeli (male and two females, mother and daughter) kept in the zoo. Seven species of the ciliates were found, among them Rhinozeta rhinozeta, R. triciliata and Prototapirella clypeata were observed in the rhinos only. The other two, Monoposthium sp. and Triplumaria sp., according to their morphology should have been identified as new ciliate species. Successful transmission of the endobionts from parents to the young rhino in the zoo was demonstrated. R. rhinozeta was investigated with the using of the methods of the light and immunofluorescence microscopy and molecular phylogeny. The composition and phylogeny of the family Cycloposthiidae were discussed.

Without their signature horn, black rhinos are less social

Without their signature horn, black rhinos are less social

LEVERAGING MACHINE LEARNING AND REMOTE SENSING FOR WILDLIFE CONSERVATION: A COMPREHENSIVE REVIEW

In recent years, the application of machine learning and remote sensing technologies in wildlife conservation has demonstrated tremendous promise. This article provides a comprehensive overview of the advancements in these fields and the impact they have had on various aspects of wildlife conservation. These technologies contribute to more efficient and effective conservation strategies by automating species identification, mapping and monitoring habitats, tracking population dynamics, detecting wildlife crime, and analysing animal vocalisations. This article talks about the development of machine learning algorithms capable of classifying bird and amphibian calls, differentiating fish species, and identifying plant species such as orchids and cacti has made automated species identification possible. Incorporating machine learning algorithms with remote sensing techniquesprovides significant advantages for mapping and monitoring habitats. This article discusses that images captured by camera trapswhen combined with acoustic analysis, can help in monitoring population by enabling automated detection and tracking. These technologies provide efficient and non-invasive approaches to monitor and manage animal populations, from estimating animal density using passive acoustics to identifying and tracking endangered species such as tigers, cheetahs, and sea turtles using camera trap images. The analysis of animal vocalisations using machine learning techniques has revealed information about species behaviour, population dynamics, and habitat quality. Examining the acoustic communication of species such as black rhinoceros and Yangtze finless porpoise has been the focus of research. Acoustic analysis provides a non-invasive method for comprehending the communication patterns of animals and their implications for conservation efforts. By utilising artificial intelligence and remote sensing data, conservationists can make informed decisions and take targeted actions to protect and preserve endangered species and their habitats. These technologies continued development and application hold great promise for the future of wildlife conservation.

Historical development of the survivorship of zoo rhinoceroses-A comparative historical analysis.

Zoo animal husbandry is a skill that should be developing constantly. In theory, this should lead to an improvement of zoo animal survivorship over time. Additionally, it has been suggested that species that are at a comparatively higher risk of extinction in their natural habitats (in situ) might also be more difficult to keep under zoo conditions (ex situ). Here, we assessed these questions for three zoo-managed rhinoceros species with different extinction risk status allocated by the IUCN: the "critically endangered" black rhino (Diceros bicornis), the "vulnerable" greater one-horned (GOH) rhino (Rhinoceros unicornis), and the "near threatened" white rhino (Ceratotherium simum). Comparing zoo animals ≥1 year of age, the black rhino had the lowest and the white rhino the highest survivorship, in congruence with their extinction risk status. Historically, the survivorship of both black and white rhino in zoos improved significantly over time, whereas that of GOH rhino stagnated. Juvenile mortality was generally low and decreased even further in black and white rhinos over time. Together with the development of population pyramids, this shows increasing competence of the global zoo community to sustain all three species. Compared to the continuously expanding zoo population of GOH and white rhinos, the zoo-managed black rhino population has stagnated in numbers in recent years. Zoos do not only contribute to conservation by propagating ex situ populations, but also by increasing species-specific husbandry skills. We recommend detailed research to understand specific factors responsible for the stagnation but also the general improvement of survivorship of zoo-managed rhinos.

Reductions in home-range size and social interactions among dehorned black rhinoceroses (Diceros bicornis)

Poaching for horns and tusks is driving declines of megaherbivores worldwide, including the critically endangered African black rhinoceros (Diceros bicornis). By proactively dehorning entire rhinoceros populations, conservationists aim to deter poaching and prevent species loss. However, such conservation interventions may have hidden and underestimated effects on animals' behavior and ecology. Here, we combine >15 y of black rhino-monitoring data across 10 South African game reserves, comprising >24,000 sightings of 368 individuals, to determine the consequences of dehorning for black rhino space use and social interactions. While preventative dehorning at these reserves coincided with a nationwide decrease in black rhino mortality from poaching and did not infer increased natural mortality, dehorned black rhinos decreased their home range area by, on average, 11.7 km2 (45.5%) and were 37% less likely to engage in social encounters. We conclude that dehorning black rhinos as an antipoaching measure alters their behavioral ecology, although the potential population-level effects of these changes remain to be determined.

THE EFFECT OF HEAVY BAG THRUST TRAINING ON THE RESULTS OF PENCAK SILAT FOREHANDS IN TAPAK SUCI ATHLETES

This study aims to determine the effect of heavy bag thrust training on the results of forehand strokes in Banyuasin black rhinoceros martial arts athletes. This study used a sample of 30 students, collecting data using the forward punch test on pecing with a stopwatch measuring instrument. The method used is a quasy experiment with a pretest-posttest one group design. The results of the forehand pretest obtained the highest score of 22 and the lowest score of 12, while the results of the forehand posttest obtained the highest score of 23 and the lowest score of 12. The treatment in this study was pushing exercises using a heavy bag thrust given for 6 weeks with a frequency of 3 times a week. Test the effectiveness using the quasy experimental method with the results of a significant "t test" ɑ = 0.05 obtained tcount = (6.6) while ttable = (1.70), then tcount &gt; ttable so that Ha can be accepted while Ho is rejected. The implication of this research is that coaches can use the heavy bag thrust training method as one of the training programs to improve the results of the forehand stroke.