Age determination of the African buffalo, Syncerus caffer Sparrman

Age criteria for the African buffalo are described. These are based on the tooth eruption sequence and on wear of the first molar. Assignment of absolute ages to the tooth eruption and wear classes has been made by reference to known-age animals and to numbers of cementum lines in tooth sections. For ageing animals to the nearest year, the normal degree of accuracy of the methods is assumed to be about ± 1/2year (1–5 years of age); about ± 1 year (5–15 years of age); and about ±2 years (15-20years of age). A field method of age determination is presented based on horn characteristics and relative body size.     

Age determination of the African buffalo, Syncerus coffer (Sparrman) in Zimbabwe

Age determination methods using teeth are described for African buffalo in Matusadona National Park, Kariba, Zimbabwe. Tooth eruption stages and age classes for sub-adult animals were established by reference to a seasonal breeding peak and known dates of death. Teeth in adult animals were allocated age classes based on wear using measurements of crown height and by reference to previously published material. Layering in the dental cement indicated the deposition of one cementum line per annum and line counts were used to assign chronological ages to individual animals. Regressions of wear on age were confirmed by independent counts of cementum lines using a predictive wear model.     

Morphology of rhinoceros platelets

Basic hematological information about rhinoceros species is limited. In this study, we have determined the platelet counts and described the platelet morphology of free-living white (Ceratotherium simum) and black (Diceros bicornis) rhinoceros using light and electron microscopy. The platelet counts of the two species were similar, but there were significant differences in platelet size as well as morphology between the species. The presence of large, nondiscoid platelet forms, resembling proplatelet or stress platelet forms, were observed in both, although not as often in the white rhinoceros as in the black rhinoceros.     

Comparison of whole mitochondrial genome sequences of northern and southern white rhinoceroses (<Emphasis Type="Italic">Ceratotherium simum</Emphasis>): the conservation consequences of species definitions

The probable extinction of the last confirmed population of northern white rhinoceros (Ceratotherium simum cottoni) in the world has ignited debate regarding its species status compared to the southern white rhinoceros (Ceratotherium simum simum). Previous studies, based on partial mitochondrial sequences, have reported conflicting results regarding the species status of the northern white rhinoceros. We use whole mitochondrial genomes obtained using Next Generation Sequencing of four northern white rhinoceros and three southern white rhinoceros using novel primers in three overlapping fragments. Phylogenetic relationships were constructed, using Maximum Likelihood, and recovered monophyletic clades for northern white rhinoceros and southern white rhinoceros. The divergence time between the two mitochondrial DNA lineages was estimated to be between 0.46 and 0.97 million years ago using Bayesian inferences. Since there are currently only three surviving northern white rhinoceros individuals these results put into sharp focus the ongoing debate regarding the methods of species definition, and in particular the consequences of such definitions in conservation management of endangered species and subspecies. We conclude that the designation of sub-species status is more applicable to northern and southern white rhinoceros.     

AGEING THE UGANDA DEFASSA WATERBUCK KOBUS DEFASSA UGANDAE NEUMANN

Chronological ages have been assigned to the defassa waterbuck of western Uganda using four complementary techniques. These are the "jaw board" method in which collected skulls are sorted into arbitrary groups based upon tooth eruption and attrition; tooth impressions taken from immobilised animals at yearly intervals; counting of cementum lines in sectioned incisor teeth, and growth of horns in young males. Using these methods an animal could be aged to within plus or minus six months.     

Induced pluripotent stem cells from highly endangered species

For some highly endangered species there are too few reproductively capable animals to maintain adequate genetic diversity, and extraordinary measures are necessary to prevent extinction. We report generation of induced pluripotent stem cells (iPSCs) from two endangered species: a primate, the drill, Mandrillus leucophaeus and the nearly extinct northern white rhinoceros, Ceratotherium simum cottoni. iPSCs may eventually facilitate reintroduction of genetic material into breeding populations.     

Age determination and body growth of the Common duiker Sylvicapra grimmia(Mammalia)

Age determination in the Common duiker Sylvicapra grimmia was investigated by analysis of tooth eruption and replacement sequence, incremental lines of tooth cementum and tooth wear in a unique collection of 48 known-age skulls, and also by analysis by post-natal body growth in known-age duiker. In both the mandible and maxilla, permanent molariform teeth were fully erupted and in wear by 26 months of age. There was little variation in the age of eruption and replacement of all molariform teeth, making this a particularly useful feature of the duiker for age determination purposes. In contrast, the variability in eruption of the incisiforms, coupled with the difficulty in distinguishing deciduous incisiforms from the permanent counterparts, placed an unexpected limitation on the use of these teeth. Although the apparent linear relationship between tooth attrition and age has potential for further investigation as an age determination technique, the cementum annuli were not correlated with chronological age. Theoretical Von Bertalanffy equations were used to analyse body growth with age. It was concluded that because the asymptote of growth was reached at such an early age, and because there is so much individual variation in growth, body growth, including horn growth, is of very limited value for age determination. Female duiker were significantly larger than males.     

Field age determination of leopards by tooth wear

Age determination is an important tool in wildlife studies. Estimating the age of animals in the field using tooth wear criteria may be subject to error as a result of variations between individuals, habitats and populations. Data on age estimation of leopards and tooth wear characteristics are lacking. Nineteen leopards in Namibia were assessed for tooth eruption and wear. Between 1991 and 1995 leopards (including 13 individuals of known age) were monitored at one year intervals ('28 leopard years') to record age and tooth wear. At the age of two years leopards had fully developed dentition. Wear started with the incisors and canines, and spread to the premolars and molars. A chronology of tooth eruption and wear in relation to age is presented. Above the age of three years, male leopards showed higher frequencies of enamel flaking and canine fractures than females.     

Determination of age in Cantabrian chamois (Rupicapva pyvenaica pavva) from jaw tooth-row eruption and wear

A tooth eruption and wear pattern useful to determine ten age classes when the horns are not available for this purpose, is described for Cantabrian chamois ( Rupicapra pyrenaica parva ) inhabiting the Cantabrian Mountains (north of Spain). In animals under eight years old, age is not significantly over- or under-estimated when using the method, however, the age of animals older than eight years is significantly under-estimated.     

Allozyme variation and differentiation in African and Indian rhinoceroses

We studied variation at 25 to 31 allozymic loci in African and Asian rhinoceroses. Four taxa in three genera were examined: African Ceratotherium simum simum (northern white rhinoceros), C. s. cottoni (southern white rhinoceros), Diceros bicornis (black rhinoceros), and Rhinoceros unicornis (Indian rhinoceros). Extremely small amounts of intraspecific variation were observed in sample sizes of 2 to 10 presumably unrelated individuals per taxon: P = .00-.10, H = 0.00-0.02. We examined demographic bottlenecks and sampling errors as possible reasons for the low levels of detectable variation. The very small intraspecific genetic distance (D = 0.005) between the two living white rhinoceros subspecies is far less than the distance that has been reported for other mammal subspecies. The mean D value of 0.32 +/- 0.11 between the two African genera was also less than expected given the divergence time of greater than 7 million years suggested by the fossil record. Rhinoceroses may be evolving more slowly at the structural gene loci than are some other mammal groups. The estimate of D = 1.05 +/- 0.24 for the African-Indian split supports this idea, as the lineage diverged at least 26 million years ago. Our results contribute to the currently available scientific information on which management decisions aimed toward saving endangered rhinoceroses should be based.     

Age determination of Reindeer introduced into South Georgia

The ages of South Georgia Reindeer collected from the introduced herds, and of carcasses from natural deaths were determined using patterns of tooth replacement and eruption, and annulations in the cementum of incisor teeth. Replacement and eruption patterns are typical of the species. The difficulties encountered with the patterns of cementum deposition on the incisors, and consequently with the assignment of age to animals with established permanent dentition, are described in detail. The overall result is the underageing of a proportion of the specimens, and the problems demonstrated are ascribed to the influence of the alien environment and oceanic climate in which the animals live.     

Ciliated intestinal protozoa of black (Diceros bicornis michaeli) and white rhinoceroses (Ceratotherium simum simum) in Kenya

The aim of this study was to survey ciliated intestinal protozoa of the black rhinoceros ( Diceros bicornis michaeli ) and white rhinoceros ( Ceratotherium simum simum ) in Kenyan National Parks. Faecal samples from 28 rhinoceroses that were chemically immobilized for translocation were opportunistically collected. Presence of ciliates was assessed using faecal floatation and sedimentation techniques. The ciliates were identified using cellular morphological features. Ophryoscoleciidae, Cycloposthiidae and Blepharocrythiidae were the three ciliate families represented. Ophryoscoleciidae had nine genera, Cycloposthiidae six genera and Blepharocorythiidae 1 genus. The dominant ciliate genus in all the rhinoceroses that were sampled was entodinium . It was found that the nutrient composition of the diet influences the diversity and numbers of intestinal ciliates, which in turn regulates the nutrient available to the animal. This interplay of nutrient composition of diet, ciliate diversity and nutritional benefits to the host has been used as an index to assess the nutritional state of ruminants. Because of the occurrence of rumenal ciliates in the hindgut fermentative chamber of the rhinoceros, such an index can be used to guide the formulation of feed mixtures for rhinoceros in captivity and remote nutritional assessments of rhinoceros both in free-range and in captivity.     

Phylogenetic relationships of the five extant Rhinoceros species (Rhinocerotidae, Perissodactyla) based on mitochondrial cytochrome b and 12S rRNA genes

A major question in rhinocerotid phylogenetics concerns the position of the Sumatran rhinoceros (Dicerorhinus sumatrensis) with regard to the other extant Asian (Rhinoceros unicornis and R. sondaicus) and African (Diceros bicornis and Ceratotherium simum) species. We have examined this particular question through the phylogenetic analysis of the complete sequences of the mitochondrial 12S rRNA and cytochrome b genes. Three additional perissodactyls (one tapir and two equids) plus several outgroup cetartiodactyls were included in the analysis. The analysis identified a basal rhinocerotid divergence between the African and the Asian species, with the Sumatran rhinoceros forming the sister group of the genus Rhinoceros. We estimate the Asian and African lineages to have diverged at about 26 million years before present.     

Palpebral vibrissae in the Sumatran rhinoceros (Didermocerus sumatrensis

The erroneous notion that palpebral vibrissae (eyelashes) are wanting from the lower eyelid of the Rhinocerotidae is attributable to Pocock (1914), whose observations were apparently made on museum skins and mounted specimens only. Examination of living and of freshly dead specimens shows such vibrissae to be present upon both eyelids in three of the five extant rhinoceros forms, viz. Rhinoceros unicornis, Diceros bicornis, Ceratotherium simum (Cave, 1969; Van den Bergh, 1970).     

Polymorphic microsatellites in white rhinoceros

The southern white rhinoceros (Ceratotherium simum simum) has suffered severe reductions in population size over the last 150 years as a result of overhunting. We optimized 10 southern white rhinoceros microsatellite loci and tested them on 30 individuals from the largest remaining population of this species. Five of the 10 loci were polymorphic with mean expected heterozygosity of 0.578, mean polymorphic information content of 0.481 and mean number of alleles 2.8. Although these data suggest low genetic variability in C. s. simum, an accurate comparison of variability awaits results of ongoing broad‐scale microsatellite surveys in this family.     

First successful artificial insemination with frozen-thawed semen in rhinoceros

The first successful artificial insemination (AI) in a rhinoceros was reported in 2007 using fresh semen. Following that success, we decided to evaluate the possibility of using frozen-thawed semen for artificial insemination. Semen, collected from a 35-36 year old Southern white rhinoceros (Ceratotherium simum simum) in the UK was frozen using the directional freezing technique. This frozen semen was used in two intrauterine AI attempts on a 30 years old female rhinoceros in Hungary. The first attempt, conducted 30 days postpartum with an insemination dose of ∼135 × 10⁶ motile cells, failed. The second attempt, conducted two estrus cycles later with an insemination dose of ∼500 × 10⁶ motile cells, resulted in pregnancy and the birth of a healthy offspring. This represents the first successful AI using frozen-thawed semen in a rhinoceros, putting it among very few wildlife species in which AI with frozen-thawed semen resulted in a live birth. The incorporation of AI with frozen-thawed semen into the assisted reproduction toolbox opens the way to preserve and transport semen between distant individuals in captivity or between wild and captive populations, without the need to transport stressed or potentially disease carrying animals. In addition, cryopreserved spermatozoa, in combination with AI, are useful methods to extend the reproductive lifespan of individuals beyond their biological lifespan and an important tool for managing genetic diversity in these endangered mammals.