bluuebunny/crossref_metadata_2025_split huggingface dataset:
Digestion in the hippopotamus
Authors: ARMAN PAMELA , FIELD C. R. 
Published: April 2008

SummaryThe hippopotamus (Hippopotamus amphibius Linn.) has an enlarged stomach, divided into: (a) two anterior diverticula; (b) a large median chamber, and (c) a posterior chamber, secreting gastric juice. Fermentative digestion occurs in (a) and (b). The anatomy and function of the stomach are discussed.Two experiments were performed to compare digestive efficiency with that of ruminants.Exp. 1. In a total collection experiment, chopped grass wasfedtoahippopotamusand five ruminants. Overall digestibility was lower in the hippopotamus, but this may have been due to keeping the animal out of water.Exp. 2. A hippopotamus and two sheep were fed chopped elephant grass (Pennisetum purpureum), digestibility being measured by total collection (in the sheep) and the chromogen ratio method. Dry matter digestibility was similar in all three animals, while digestibility of crude protein was higher in the hippopotamus.
Census of the Kafue lechwe by aerial stratified sampling
Authors: BELL R. H. V. , GRIMSDELL J. J. R. , LAVIERNE L. P. VAN , SAYER J. A. 
Published: April 2008

SummaryThe Kafue lechwe population of the Kafue Flats, Zambia, was counted four times within a 26‐month period (April 1970‐June 1972) by aerial stratified random sampling. The censuses gave good agreement which did not differ statistically. By combining the data for the three most precise surveys, the estimated population is 93 975 with 95% confidence limits of ± 8563 (or ± 9‐1%). A method of sampling was used which is based on calculation of animal densities on a linear basis, instead of on densities per unit area. This method has several advantages and is discussed in relation to the problems involved in aerial census. The past and present status of the Kafue lechwe population is reviewed.
Prey selection and annual harvest of game in a rural Zambian community
Authors: MARKS STUART A. 
Published: April 2008

SummaryThe selection and hunting patterns of Valley Bisa hunters were studied as part of a broader ecological investigation of human communities between the two sections of the Luangwa Valley Game Reserves in Zambia. This article provides information on the frequency and duration of hunts recorded for 1 year, yields of individual hunters, prey selection, frequency of kill, community meat supplies and the effect of human and carnivore predation on population levels on a study area of some 155 km2.Individuals who hunted were classified into four categories–resident, transient, occasional, and official, dependent upon their role in the community, length of time spent on the study area and their village of primary residence. The most frequent hunters were residents followed in rank order by officials, transients and occasionals. Hunts were of shorter duration during the dry season, when game was close to villages, than during the wet season.Generally hunters who owned or had access to modern weapons were more successful in their pursuits of game than were those who used muzzle‐loading guns. A total of 27 451 kg of meat (carcass yield) was made available to 466 local residents during the course of the year; 40% of this was attributed to the activities of the game guards. Valley Bisa hunters killed primarily buffalo, impala, warthogs, and waterbuck; most of these were males and adults. The kills recorded for carnivores suggest that they took primarily female buffalo and zebra. There was no evidence to suggest that either type of predation was damaging to the game herds on the study area.
Counting the Serengeti migratory wildebeest using two‐stage sampling*
Authors: NORTON‐GRIFFITHS M. 
Published: April 2008

SummaryA method for sample counting the Serengeti migratory wildebeest using vertical aerial photography to sub‐sample randomly located transects is described. The population estimate achieved was 754 028 animals, with 95% confidence limits of ± 8‐5% of the population estimate. The application of this method to other wildlife populations is considered.
A review of the age determination of mammals by means of teeth, with especial reference to Africa
Authors: SPINAGE C. A. 
Published: April 2008

SummaryA growing requirement exists to determine the ages of the larger African mammals, concomitant with increasing management. Teeth offer the most practicable means of age determination, but no wholly reliable method, based on teeth, has been demonstrated. Tooth structure, growth and function, are considered, and related to methods of age determination. Methods are divided into those separating groups, and those for determining the chronological ages of groups. The various methods used in these two procedures are evaluated. It is pointed out that studies on the most promising method, cementum line counts, have been neglected in Africa, while methods of determining the ages of large carnivores are virtually uninvestigated, and there is a lack of basic studies describing tooth growth and changes for most large African mammals.
Population structure and dynamics in the African Fish Eagle Haliaeetus vocifer (Daudin) at Lake Naivasha, Kenya
Authors: BROWN L. H. , HOPCRAFT J. B. D. 
Published: April 2008

Summary(1) The population structure and breeding success of the Fish Eagle Haliaeetus vocifer (Daudin) at Lake Naivasha was assessed in 1970‐71, as part of a wider pesticide residue survey. The figures obtained have been combined with those of an earlier population and breeding survey in 1968‐69.(2) Population structure was assessed by plumage criteria, dividing the total adults, subadults (early and late), 2 year‐olds, and recent immatures. Between 1968 and 1971 there was an increase of about 40% in the adult population on the lake, but immatures increased by only 11 %. The adult/immature ratio was 83: 17% in 1968‐69 and 85‐6: 14‐4% in 1970‐71.(3) From these data it appears that the age of Fish Eagles as adults lies between 16 and 24 years, with a total age of 20–28 years. This is much longer than observed wild life spans in some other eagles.(4) Although the total population rose, the number of breeding pairs was constant, fifty‐six in each year of survey, with minor changes.(5) Breeding success overall is about 0–47 young/pair/annum for both years combined, varying greatly between different parts of the lake and from year to year. As only two thirds of all pairs lay, and some of these fail, this equals 0–74 young/pair which bred and 1–28/successful nest.(6) Breeding success at Lake Naivasha is considered to be unaffected by human interference, either deliberate or casual.(7) Analysed by habitat, pairs which bred near wide lagoons within the papyrus were markedly more successful than those with access only to open water (0–55 young/ pair/annum overall cf. 0–29). The possibility that this is due to superior food opportunities in the lagoon habitat is discussed. Fish Eagles can catch birds and fish, and pirate other species kills in lagoons, whereas they must catch all their own fish prey in the open lake sites.(8) Preliminary observations of diurnal behaviour do not indicate that Fish Eagles with access only to open water have any more difficulty in catching prey than those in lagoons, so that the relation between food supply, habitat, and nesting success remains obscure.
Regulation, and population models for a tropical ruminant
Authors: SINCLAIR A. R. E. 
Published: April 2008

SummaryBy annual measurements of population size, fertility and recruitment on a buffalo population in the Serengeti it has been possible to construct a model that predicts the equilibrium level of this population. This model also suggests that the population is increasing towards an equilibrium position, and that adult mortality is the only regulating mortality needed to achieve this equilibrium. Juvenile mortality shows large fluctuations from year to year and potentially is the most important mortality in causing fluctuations in population size.By extrapolating the model population backwards in time it is possible to observe that the real population has experienced a higher mortality or lower fertility in the past, and there is evidence from the rinderpest disease at that time which suggests that this could have been a possible cause. The models can be adapted to incorporate changing conditions either from habitat change due to the population itself or from environmental change and hence this approach is potentially useful in solving certain population problems.
Elephant mortality in Tsavo National Park, Kenya
Authors: CORFIELD TIMOTHY F. 
Published: April 2008

Summary(1) The scale and pattern of the elephant mortality occurring in Tsavo National Park during the dry years 1970 and 1971 was investigated.(2) Total numbers were estimated from an aerial stratified systematic sample, and a correction made for juvenile carcasses lost through disintegration. The overall total was estimated at c. 5900 although this included a somewhat arbitrary addition for juveniles estimated to have disintegrated during the study period.(3) The aerial census provided the basis for an analysis of the spatial distribution of carcasses.(4) The age distribution of the mortality was determined from the collection of found jaws, after the correction made for collection bias and carcass disintegration. Sex composition was determined from a large sample of known‐age tusks.(5) Age and sex‐specific mortality were calculated, which provided interesting comparisons with the pattern of more normal years. There was good evidence to show: (a) a prolonged phase of high juvenile mortality; (b) raised overall rates; (c) preferential adult female mortality.(6) The spatial distribution of the mortality coincided with: (a) areas of high, recent immigration; (b) areas of low and erratic rainfall; (c) areas of profound vegetation change. Within these areas it was concentrated near permanent water. Its occurrence in time coincided with 2 years of low rainfall and prolonged dry seasons.(7) The report concludes with some possible implications of the mortality for Tsavo National Park.
The distribution, density and biomass density of lizards in a semi–arid environment of northern Kenya*
Authors: WESTERN DAVID 
Published: April 2008

SummaryAn attempt was made to determine the species composition, density and biomass density of lizards in some of the principal land units in South Turkana. Thirteen species were recorded. Density estimates were determined from quadrat sampling in representative habitats.Because the number of lizards active was found to vary with time of day and temperature, minimum density estimates were obtained by confining counts to peak activity periods. Biomass density was calculated from the product of species density and the mean population weight measured from shot specimens. The biomass density estimate of the lizard fauna was found to be about 4–5% of the large mammal fauna, and appreciably more in the more arid land units.The species composition of South Turkana lizards show affinities to the Somali fauna, though not to the extent of the East Rudolf fauna, suggesting a more recent penetration of arid–adapted species.
Food searching in griffon vultures
Authors: HOUSTON D. C. 
Published: April 2008

SummaryObservations are presented on food searching in griffon vultures. To locate food directly, griffon vultures do not use a sense of smell but rely on vision. However, most birds locate carcasses indirectly—by watching the activities of neighbouring birds. The method of food searching is described and the number of birds which arrive at a carcass is shown to depend on the amount of food that is available. Birds do not hold feeding ranges, but travel widely during food searching, one bird travelling 180 km in 6 days. The density of searching birds varies greatly according to the density of ungulates in an area, birds being most numerous over high ungulate concentrations. The altitude at which birds search also varies, birds flying at higher altitudes over areas of low ungulate density and at lower altitudes over ungulate concentrations. These variations in searching density and height are shown to affect the efficiency of food searching. Carcasses are located rapidly and the food consumed quickly in high ungulate density areas, while in low ungulate density conditions carcasses can take a long time to be located. It is concluded that griffon vultures are more likely to find food and are better able to compete with mammalian competitors by searching over migratory ungulate herds than over areas containing resident ungulate species. Their adaptations for gliding flight enable these birds to follow these migratory ungulates throughout the year.
The age of puberty of the hippopotamus (Hippopotamus amphibius Linn.) in the Luangwa River in eastern Zambia
Authors: SAYER J. A. , RAKHA W A. M. 
Published: April 2008

SummaryAs part of a study of the ecology of a high density hippopotamus population (Hippopotamus amphibius) in the Luangwa river in eastern Zambia, a shot sample of 176 males and 161 females was examined. All animals were classified according to age (0–43 years). The female reproductive organs were removed, dissected, examined, and the lactational status was noted. Ovaries and corpora Iutea were weighed, sliced, and all follicles > 5 mm in diameter were recorded. The testes of the males were dissected and weighed. Indications of puberty and maturity in the female were observed in some animals at an age of about 7 and 8 years respectively; but some animals were still not breeding until 20 years of age and the ages at which 50% of the female population reached puberty and maturity (Laws & Clough, 1966) were 11 and 13 years respectively. In the male, puberty begins at an average age of 6 years and maturity is reached at approximately 8 years of age. The data showed that lactation has no effect on ovarian weight or activity. The weight of the corpus luteum during pregnancy (36–72 ± 2–65 g) is significantly (P < 0–01) greater than that observed in non‐pregnant animals (16–64 ± 2–46 g). Multiple ovulation occurs in 8–10% of the animals.
The ovary of Günther's dik‐dik, Madoqua guentheri Thomas
Authors: KAYANJA F. I. B. , SALE J. B. 
Published: April 2008

SummaryThe ovaries of five Günther's dik‐dik were investigated using histological techniques. The structure of the ovary and corpus luteum as well as the growth and atresia of the follicles are described.
Movements of the migratory wildebeest population in the Serengeti area between 1960 and 1973
Authors: PENNYCUICK LINDA 
Published: April 2008

SummaryData on the monthly distributions of the Serengeti migratory wildebeest population between June 1960 and May 1973 have been analysed.It has been shown that the population performs an annual migration, spending the wet season on the Serengeti plains, then moving west towards Lake Victoria at the beginning of the dry season, and later north to the northern extension of the Serengeti National Park or into the Masai Mara Game Reserve in Kenya. The wildebeest return to the plains as soon as the rain begins, but if this is delayed they may move south‐west from the northern areas into the corridor first.Annual differences in the pattern of the migration can be correlated with differences in rainfall. The rainfall affects particularly the timing of the movements of the wildebeest on and off the plains, and the extent to which they utilize the northern areas.A large increase in the size of the population over the years studied has resulted in a greater utilization of the northern areas.It has been shown that about half the total range of the wildebeest population is outside the boundaries of the Serengeti National Park, and it is therefore important that these areas should be protected if such a large population is to survive.
Climate and the food habits of ungulates on Galana Ranch
Authors: FIELD C. R. 
Published: April 2008

SummaryVegetation communities and the climate during the study are described for the ranch. From 1970 to 1972 feeding observations were made during 21 months on semi‐domesticated buffalo, eland and oryx and on cattle using the feeding minutes technique. The animals were observed in three plant communities as follows: (1) riverine vegetation with eroded slopes; (2) a catena of dry grassland and bushed woodland on grey and red soils; (3) moist coastal bush with grassland patches. Observations included periods of high and low rainfall in each community although these were irregular. Plant samples from the more common species were collected at intervals for chemical analysis.Early in the plant growth period all species graze within the grass/herb layer. As the grass matures eland gradually concentrate on browse plants while the other species continue to graze and to browse a little. When deciduous browse plants lose their leaves eland rely on evergreen shrubs.Annual and drought‐tolerant perennial grasses form the main diet of oryx while buffalo and cattle both eat bulky perennial grasses.Analyses of browse leaves show that during dry periods they are comparatively rich in protein when compared with grasses. The requirements of eland for protein rich food explain why they migrate over the ranch and do not do well when restricted. The possible influence of irregular rainfall on the eland population is discussed.The oryx is the smallest of the three grazers and therefore able to be more selective. The annuals which they eat form standing hay which is fairly nutritious, while their small mouths permit selection of protein‐rich parts of perennial grasses. Cattle and buffalo require large quantities of feed which may be of poor quality. Their large mouths are unable to select the protein‐rich parts of perennial grasses and this puts them at a disadvantage during a prolonged drought.
Utilization of waterholes in Tsavo National Park (East)
Authors: AYENI J. S. O. 
Published: April 2008

SummaryUtilization of waterholes by wildlife was studied between April, 1973 and July, 1974 in Tsavo National Park (East), south of the Voi river. Seasonality was an important factor which influenced the various aspects of waterhole utilization. The numbers of the herbivores utilizing the waterholes increased during the dry season but fell during the rains. Some ungulates also moved near to the artificial waterholes in the dry season but moved away from them during the rains when they drank from natural water‐holes formed in clay pans filled with rain water.A basic pattern of waterhole utilization dominated by small (adult‐size) species during day‐time 06.00–18.00 hours and larger species at night 18.00–06.00 hours is described. The separation in times of arrival and deparature peaks of waterhole utilization, and average coincidence of percentages of paired species populations are used to show that big‐game attained a measure of time‐spaced ecological separation at the waterholes.The water relations of some day‐time and night‐time drinkers are discussed. From the baseline study the management implications of the development of additional waterholes in the park are discussed.
The savanna ecology of Kidepo Valley National Park
Authors: FIELD C. R. , ROSS I. C. 
Published: April 2008

Summary(1) Food habits of elephant and giraffe were recorded in short sample periods over several years using the feeding minutes technique. (2) Twelve species of common plants were collected on these occasions, separated into their main parts and analysed chemically. (3) Damage to trees was also recorded at intervals. (4) Fifty‐nine species of plant were eaten by elephant. During wet months their diet was predominantly grass but during dry months woody vegetation became more important. Giraffe were observed eating from thirty‐nine species of plant which were almost entirely browse throughout the year. At least eighteen of these species were also eaten by elephant. (5) Three of the browse species most important to giraffe were also important to elephant in dry seasons. In the driest month the species eaten by giraffe formed more than two‐thirds of the observed diet of elephants. (6) Chemical analyses of plants show that browse leaves had a higher level of protein, fat and minerals than most other plants. (7) The trunk of an elephant and the tongue of a giraffe are highly sensitive organs which permit food selection. Elephant in particular appeared to alter their food habits seasonally and it is suggested that this may be an attempt to obtain a balanced intake of nutrients. (8) Due to the effect of elephant and other agencies there is an accelerating decline in Acacia gerrardii woodlands. Browsing and fire are independently preventing their regeneration. (9) The extensive overlap of food requirements on preferred but diminishing browse resources implies potential if not already existing competition between elephant and giraffe. (See Part III.)
The savanna ecology of Kidepo Valley National Park, Uganda
Authors: ROSS I. C. , FIELD C. R. , HARRINGTON G. N. 
Published: April 2008

SummaryCensuses indicated similar elephant densities in some habitats to those in certain other East African Parks where woodland has been almost completely destroyed. Giraffe densities were low. Herd structure indicated a healthy elephant population; but poor recruitment in the giraffe population.Policy for the national parks is discussed. It is suggested that it is not in the interests of Uganda or science to allow Kidepo Valley Park to become dominated by elephant in the same way as Kabalega and Rwenzori Park. Evidence that this is happening under current elephant use is strong. Cropping of two thirds of the elephant in the Narus valley is recommended. The revenue from cropping should be used for essential fire control measures and for a monitoring programme to ascertain optimum elephant numbers. Elephant should not be cropped in the absence of fire control.
Density and biomass of ungulates in Tsavo East National Park, Kenya
Authors: LEUTHOLD WALTER , LEUTHOLD BARBARA M. 
Published: April 2008

SummaryIn view of the substantial vegetation changes in Tsavo National Park and their possible effects on the herbivore fauna, this study was undertaken to obtain quantitative information on densities of several ungulate species and their biomass. Road strip counts (belt transects) constituted the main method used, supplemented by aerial counts in parts of the study area. Densities of most ungulate species are rather low, the maximum of 2–25 per km2 being attained by zebra in the southern poition of the study area. There are significant differences between two parts of the study area, related to differences in vegetation types. Mean biomass density is around 4000 kg/km2, of which ⅔‐¾ is made up of elephants. Total biomass density compares well with that in areas of similar climatic conditions but is much lower than that in moist savannas of western Uganda and Zaire with higher rainfall.
Feeding and social behaviour of the striped hyaena (Hyaena vulgaris Desmarest)*
Authors: KRUUK HANS 
Published: April 2008

SummaryObservations are presented on food, foraging behaviour, ranging and some social behaviour patterns of the striped hyaena; these observations are compared with similar ones on spotted hyaenas. Striped hyaenas are more omnivorous than spotted ones, scavenging a great deal and eating insects, fruits and small vertebrate prey. However, the diets of the two species have several food species in common, and there is competition in the relatively small area where the geographical ranges and habitats of the two hyaenas overlap.Striped hyaenas are solitary, and they show several behavioural adaptations to this. The relationship between the hyaenas' social organization and resource exploitation is discussed.