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Notes on Zambian rodents and shrews
... Dierk. 1980, 15: 95-98 C.M. Swanepoel Gwebi College, P. Bag 376B, Salisbury, Zimbabwe Received 10 August 1979accepted 30 December_1979The breeding patterns of most African Muridae appear to be seasonal, with a summer peak (Smithers 1971;Delany 1972;Sheppe 1973;Cheeseman & Delany 1979). The breeding pattern of Praomys natalensis follows this trend (De Wit 1972;Delany 1974) although there are records of breeding throughout the year in some areas (Coetzee 1965;Smithers 1971) but with summer peaks and troughs in winter. ...
... The mice caught were sexed, marked, weighed and their breeding condition noted. In the male the criterion used to determine breeding condition was the position of the testes (Brooks 1974;Sheppe 1973). In the female, the criterion used were actual signs of pregnancy (Brooks 1974;Delany 1972). ...
... There does, however, appear to be some effect on the male in that the age at which the testes become scrotal is delayed during the non-breeding season (Table 1).Newsome (1969)proposed that availability of breeding sites may play a role in determining the breeding season; with rainfall the soil would be softer and thus burrows dug easily. This might be of importance where burrows/holes are unavailable at other times of the year, such as the water level rising in a flood plain area (Sheppe 1973). However, in the present study holes were available throughout the year. ...
As part of a demographic study of Praomys natalensis in an agricultural area on the Rhodesian highveld, a preliminary investigation was carried out into some of the factors which might be of importance in determining the timing of its breeding season. Information on breeding and nutrition was obtained by both live and snap trapping. Breeding was confined to the late summer months in natural grassland areas but occurred in winter in wheat fields. Availability of nesting sites was adequate at all times. Analysis of stomach contents indicated that the protein content of the diet was adequate for breeding in all seasons. The possible influence of green grass and insects in the diet is discussed.Deel van –n demografiese studie op Praomys natalensis in –n landbougebied op die Rhodesiese hoëveld was –n voorlopige ondersoek na sommige faktore wat van belang"kan wees om die tyd van die teelseisoen vas te stel.lnligting oor teling en voeding is verkry van diere wat lewendig of dood gevang is. In ongerepte grasvelde was teling beperk tot die laat somer maande, maar het gedurende die winter geskied in koringlande. Daar was altyd genoeg skuilplekke. Analises van maaginhoude het getoon dat daar deurgaans genoeg protejene in die dieet was om teling te verseker. Die moontlike invloed van groen gras en insekte word ook bespreek.
... The spiny mouse is a nocturnal, terrestrial rodent which occurs mainly in rocky habitats and is distinguished by thick and hard spine-like hair at the back which is characteristic of the genus (Sheppe, 1973; Pienaar, Rautenbach & de Graaff, 1980; Skinner & Chimimba, 2005). Acomys spinosissimus is relatively widespread in Africa south of the equator and can be found in Tanzania, the Democratic Republic of Congo (DRC), Zambia, Malawi and in southern Africa (Mozambique, Botswana and the north-eastern parts of South Africa) (Skinner & Chimimba, 2005). ...
... Acomys spinosissimus is relatively widespread in Africa south of the equator and can be found in Tanzania, the Democratic Republic of Congo (DRC), Zambia, Malawi and in southern Africa (Mozambique, Botswana and the north-eastern parts of South Africa) (Skinner & Chimimba, 2005). The little available data suggest that this species breeds seasonally during the warm and wet summer months in Zambia (Sheppe, 1973) and southern Africa (Smithers, 1971; Pienaar et al., 1980). In this study, we investigated the seasonality of reproduction in female A. spinosissimus by using histology of the ovaries and monitoring the circulating concentrations of progesterone in the blood monthly from April 2007 until August 2008. ...
... Our data on seasonality of reproduction correspond partly with the results found by Sheppe (1973) for A. spinosissimus in Zambia and Smithers (1971) in Botswana. Both studies demonstrated a breeding season for A. spinosissimus during the warm and wet summer months, however, both recorded pregnant females until March and April. ...
Many mammal species reproduce seasonally because of annual fluctuations in temperature, rainfall and photoperiod in often nutritionally challenging habitats. The reproductive biology of many small southern African mammals is largely unknown and in critical need of study. We investigated the breeding pattern of the female spiny mouse (Acomys spinosissimus) from South Africa. We examined the ovarian development, follicular growth, circulating plasma progesterone concentrations and the reproductive status of wild-caught adult female spiny mice sampled over a 12-month period while also correcting for body mass and age. From these data, we conclude that female A. spinosissimus breed seasonally. The main breeding season of the spiny mouse is between September and January, with plasma progesterone concentrations being elevated, ovarian volume and primary, secondary, tertiary and Graafian follicle numbers as well as the corpora body number being the highest and pregnancies occurring during this period. Females were reproductively inactive from February through to August. The breeding season coincides with the onset of the rainy season in the habitat, which starts around September and ends in April. Rainfall, in association with an increase in primary productivity and hence higher food availability, might be the most important factor shaping reproduction in the female spiny mouse.
... The mean number of foetuses observed in 43 pregnant females collected during the 1976 breeding season was 12,8 (range 8-21). This number is similar to those reported by Sheppe (1973) for P. natalensis from the Kafue Flats (January -March) and Mfuwe (May -June) in Zambia. Mean number of embryos per pregnant female, however, declined as the breeding season progressed: 14,9 in February, 14,0 in March, 12,2 in April and 10,0 in May. ...
... 49 Sheppe ( 1972) found that P. nata/ens is on the KafueRats of Zambia lost 25% of their body mass during the dry season and the present results are in agreement. Food scarcity (Sheppe 1973) is probably a major cause of loss of body mass in P. nata/ensis. The increase in body mass late in the dry season and early in the rainy season is, however, difficult to explain as food was still scarce at this time. ...
An old quarry, 2,5 hain size near Livingstone in southern Zambia was kill-and live-trapped between September 1974 and December 1976 to determine ecological relations among. rodent species inhabiting it. Seven species were found to comprise the old quarry rodent community. Praomys natalensis was by far the most common although Saccostomus campestris and Lemniscomys griselda were also abundant. Four species (Tatera leucogaster, Steatomys pratensis, Mus minutoides and Aethomys chrysophilus were rare. Food and micro-habitat preferences of S. campestris and P. natalensis appeared similar. Seasonal fluctuations characterized the P. natalensis population while L. griselda was absent from the site during the latter part of the rainy season and early in the dry season. Pre-weaning survival of P. natalensis was very low, particularly early in the breeding season. The survival of the trappable population was good but declined following a burn at the study site. P. natalensis recruited into the population from May-July, lost between 20 and 35% of their body mass during the August-October period. Body mass increased as rodents attained sexual maturity early in the rainy season.
... Monthly rainfall in mm for Morogoro 1929Morogoro -1935Multimammate rats in Zambia also start reproducing soon after the onset of rains (Chidumayo 1984); the rainy season has the same timing as in Tanzania, but it is not bimodal: rains start in October-November and continue until April with one peak somewhere in between (Fig. 7). Sheppe (1973) reported a Mastomys outbreak in 1966. Rainfall was abundant that year but not extraordinary and the temporal distribution of rain was normal for the region, although rather much of it fell during the first part of the rainy season. ...
During 3 years we studied a population of multimammate rats, Mastomys natalensis (Smith 1834), in Morogoro, Tanzania. Data were collected in both removal and capture-recapture schemes. We present evidence that patterns of growth and reproduction were related to onset and abundance of rains. This partially explains differences in densities. Additionally, we investigated available literature data and related them with climatological data. A scenario is presented which enables us to predict how densities of multimammate rats may evolve in the following year and whether there will be a risk of outbreaks. The use and implications of this scenario in planning control actions are discussed.
... The present study was undertaken to unravel the 93 reproductive biology of the spiny mouse (Acomys spinosissimus). The spiny mouse is 94 a small, nocturnal rodent which inhabits rocky outcrops and riverine habitats where it 95 finds shelter under boulders and rocks as well as in termite mounds (Sheppe, 1973; 96 Pienaar et al., 1980; Fitzherbert et al., 2007). It has a widespread distribution across 97 Africa, south of the equator, and is found in Tanzania, the Democratic Republic of 98 ...
Seasonal reproduction is a common characteristic of many small mammals which inhabit seasonal environments in temperate regions, the sub-tropics as well as the tropics. It is important for an animal to reproduce during the most favourable time of the year to ensure the survival of the young and maximize reproductive success. In southern Africa, female spiny mice (Acomys spinosissimus) breed during the warm and wet spring and summer months, whereas the reproductive pattern of males is unknown although an opportunistic breeding pattern has been implicated. We investigated testes mass and volume, seminiferous tubule diameter, spermatogenesis and plasma testosterone concentrations in a South African population of male spiny mice on a 2-monthly basis over one year. Testes mass and volume started to increase in July/August and was high from September until December. Seminiferous tubule diameter and spermatogenesis increased during the same months. Plasma testosterone concentration was elevated from July/August to November/December. Development of the reproductive characteristics of male spiny mice was correlated with high rainfall and high ambient temperatures, but reproductive development had already started during the dry season and the coldest months. This shows that reproductive development in males may not be dependent on climatic conditions, and other factors, such as photoperiod, may trigger the onset of reproduction. The data, however, suggest that A. spinosissimus is a true seasonal breeder with reproduction confined to the spring and summer months in southern Africa.
... Hubert et Adam (1975) trouvaient des portées moyennes de 4 à 6 petits chez T. pygargus et 3 à 5 petits chez T. gracilis. Différentes données sur la fécondité existent dans la littérature, Coetzee (1975) et Sheppe (1973 indiquant que la taille des portées est plus élevée en fin de saison de reproduction, Neal (1977) observant que cette taille diminuait tout au long de la saison de reproduction, tandis que Hubert (1982) signalait un nombre maximum d'embryons en milieu de saison de reproduction, avec un nombre moyen d'embryons par femelle gestante pouvant varier du simple au double dans une même localité, d'une année sur l'autre Dans le genre Taterillus, malgré l'absence de femelles gestantes parmi nos rares captures sur les quadrats CMR, nous avons observé que les populations étaient quelquefois constituées de plus de jeunes que d'adultes en pleine saison sèche comme c'est le cas en avril 2001, ce qui confirme la double période de reproduction chez cette espèce, décrite par Hubert (1982) qui disait que la première se passait avec celle de M. etythroleucus en début de saison sèche et que la deuxième avait lieu en pleine saison sèche, entre février et mai. Selon lui, la seconde reproduction peut ne pas avoir lieu, comme cela semble avoir été le cas pendant les deux premières années de notre étude. ...
Many mammals, ranging from antelope to elephant shrews, eat ants and termites. The specialized mammalian myrmecophages (ant- and termite-eaters) such as aardvarks and pangolins have long drawn attention, but little work has been done on general predator-prey relationships between mammals and ants and termites.
A unique, global scope provides a much needed base for comparison Detailed case studies ideal as a reference for students and professionals Thorough review of management and policy issues supply practitioners with guidelines and suggestions Written both as a textbook and as a professional reference book, Sustaining the World's Wetlands: Setting Policy and Resolving Conflicts contains detailed case studies of wetland management worldwide. Examinations of international wetland policy in Europe, Africa, Asia, and North America generate a discussion of the differences between wetland management issues in developed and developing countries, and culminate in suggested strategies for the future of wetland management. Key themes addressed in the case studies include the tradeoffs between sustainable use of wetlands for food, fuel, and fiber versus the protection of ecosystem diversity and stability, and the respective roles of international NGO's, national and regional government, and local community-based organizations when faced with wetland management issues. With its global scope and its emphasis on policy and management analysis, Sustaining the World's Wetlands is a unique and valuable tool both for students and for practitioners. © Springer Science+Business Media, LLC 2009. All rights reserved.
1. Rainfall data were collated for years preceding historical outbreaks of Mastomys rats in East Africa in order to test the hypothesis that such outbreaks occur after long dry periods. 2. Rodent outbreaks were generally not preceded by long dry periods. 3. Population dynamics of Mastomys natalensis rats in Tanzania are significantly affected by the distribution of rainfall during the rainy season. 4. All previous rodent outbreaks in Tanzania were preceded by abundant rainfall early in the rainy season, i.e. towards the end of the year. 5. A flow chart is constructed to assess the likelihood of rodent outbreaks up to 10 months beforehand, utilizing rainfall data.
In parts of sub-Saharan Africa, as well as South America, India, and southeast Asia, interior riverine wetlands are stressed
or altered by dams and reservoir projects for hydroelectric, irrigation, and flood control “benefits” (Dugan 1988, Nelson
et al. 1989, Scudder 1989). Resultant impacts from hydroelectric alteration and lack of flooding downstream affect both biodiversity
and human use of floodplain wetlands for agriculture, fiber, and medicinal plant usage (Duggan 1988, Mathooko and Kariuki
2000, Tockner and Stanford 2002).
Four four-toed elephant-shrews Petrodromus tetradactylus were radio-tracked at Sodwana Bay National Park in the dune forest situated on sand-hills above the high water mark along the east coast of KwaZulu-Natal, South Africa. Tracking was conducted over 5 months during summer and the results were used to explore the use of space by the elephant-shrews. None of the topographical or vegetational features of the study area had any great influence on the distribution of the elephant-shrews. Both sexes occupied highly symmetrical (circular) home ranges that were similar in area. The elephant-shrews showed considerable fidelity to their home ranges, which had long-term permanence, but were not obviously defended as territories. Activity of the elephant-shrews, monitored for the first time during 24 h in the wild, was strongly crepuscular, with intense activity around dusk and dawn, much reduced during the day, with complete cessation of activity at night. There was considerable overlap between individual home ranges, suggesting a high population density. This may be related to the mild climate and ample food supply of the dune forest of northern KwaZulu-Natal or to the season of observation.
Des populations de rats à mamelles multiples Mastomys natalensis A. Smith ont été étudiées dans trois endroits proches de Livingstone, dans le sud de la Zambie, de janvier 1974 à décembre 1976. La strueture d'âge des populations varie saisonnièrement avec l'arrivée des classes jeunes de février à juillet. La proportion des sexes est différente selon l'état de la reproduetion, selon les conditions de piégeage et peut-être aussi du fait d'une mortalité différentielle. Le poids du corps varie avec l'âge et la période de l'année. Les femelles sont gestantes de décembre à juin. Le nombre des embryons par femelle pleine varie selon la période de reproduction, l'âge de la mècre et la localité. Les populations montrent deux pics d'abondance: Tun au cours de la saison des pluies est cause par l'immigration; l'autre au début de la saison sèche est du à la reproduetion. Les populations qui habitent les savanes soumises à l'action du feu déclinent fortement, ou même disparaissent, après la destruetion du couvert herbeux au cours de la saison sèche. Les populations qui vivent dans des zones couvertes de buissons ne varient pas beaueoup, leur habitat étant plus stable.
This study summarizes the data on the population structure of Deomys ferrugineus, Hybomys lunaris Lophuromys dudui on the mainland and Praomys jacksoni on the mainland as well as on islands on the Congo River. All species at these three localities show a stable population structure without seasonal variation. Reproduction on the mainland populations is probably continuous year-round, with subadult presence during the whole year. The island populations of P. jacksoni have a different population structure from the mainland population, probably caused by the periodic inundations. The sex-ratio is even for L. dudui and H. lunaris. For P. jacksoni and D. ferru- gineus however, more males were captured on the mainland. On the islands, the sex-ratio pattern is not clear cut and differs between years. No clear seasonal variation in sex-ratio has been found in our populations.
The relationship between Protea humiflora and its small mammal pollinators was investigated at the fynbos/karoo ecotone in the Riviersonderend Mountains, South Africa. Acomys subspinosus occurred in low densities at Jonaskop, with around 3.9 ± 2.0 (mean ± 1 S.D.) individuals/ha (six months of trapping). Low repeat trapping may result may result from low survivorship or emigration from the area after flowering of P. humiflora. Mean mass of A. subspinosus was lower than published values due to a high proportion of juveniles in the population, coinciding with P. humiflora flowering. Comparison with other published data suggests that A. subspinosus is an opportunistic breeder. This contrasts with its geographically nearest congener, A. spinosissimus, in which breeding is restricted to the summer months, but is similar to data for other Acomys species. Minimum home range areas (-0.23 ha, minimum overnight distance 39 ± 6 m), were relatively high and may indicate a species surviving on thinly dispersed resources.
The archaeological site of Mumbwa Caves in central Zambia has produced a long sequence of micromammalian remains, although this has not yet been dated directly. These remains represent at least 27 species, four insectivores, two bats and 21 rodents. Such diversity is comparable to that found in other assemblages from southern African archaeological sites in the savanna biome. The lack of forest shrews (Soricidae, Myosorex spp.) and golden moles (Chrysochloridae) indicates that the current absence of these groups from Zambia is longstanding, if they were ever present. Not all specific identifications are firm, due to the broken and/or scarce nature of the material. Failing firm evidence to the contrary, it has been accepted that the most likely species, in modern terms, is the one that was present in the past. However, the probable presence of Rhabdomys pumilio, which is anomalous today, suggests that this conservative approach may not always be correct. Once sample sizes have been increased, the Mumbwa Caves micromammal remains have the potential to contribute to knowledge of past distributions, species relationships and changes in community composition. This, in turn, could have a bearing on decisions concerning the establishment of nature reserves.
Ticks were collected from 2136 small mammals, comprising 5 bats (5 species), 14 elephant shrews (3 species), 84 Crocidura shrews (5 species), 25 hares (1 species), 10 small carnivores (3 species), 3 hyraxes (1 species) 1998 rodents (33 species), and from 41 birds (19 species) at various localities in Zambia. From these hosts 6568 ticks (4384 larvae, 1686 nymphs, 317 males and 181 females) were recovered. Twenty-three species were positively identified and nineteen other species were assigned to genus or species-group. Host and tick records are tabulated by regions collected and for each of the two regions with the largest collections, the records are tabulated by months. The ticks collected in the high montane area near the Malawi border differed significantly from collections in other areas studied, reflecting host and climate differences. In the two areas tabulated by month, most of the immature ticks were recovered in the cool dry winter months (April to August).
Hydroelectric dams have markedly altered the extensive floodplain of Zambia's Kafue River Flats. Before the dams were built in the 1970s, some 6,000 km ² of floodplain were under water for several months each year, permitting a dense growth of grasses and forbs that supported large populations of ungulates and waterbirds. Now a dam at the lower end of the Flats has permanently inundated parts of the floodplain, and a dam at the upper end has reduced the seasonal flooding, so that much of the floodplain is now probably permanently dry. When the Flats was revisited in 1983, the effect of the dams was obscured by the effects of drought, hunting, and human use.
In 1983, plant growth in most places was much less luxuriant than it had been before impoundment. Bird populations seemed much smaller than formerly, and populations of at least some ungulates had declined. The most abundant ungulate, the Lechwe ( Kobus leche ), is reported to have declined by about half in the last eight years.
Population dynamics and habitat preferences of the dusky rat, Rattus colletti , were examined in the seasonal wetlands of the South Alligator River. Northern Territory, between late 1979 and 1982. Demographically, the species is characterized by short‐term seasonal shifts between habitats superimposed on a longer‐term irregular pattern of prolonged breeding and population irruption, followed by periods of relative rarity. These patterns are determined by the train of climatic events. The flexible life history strategy and movement patterns of R. colletti reflect fine‐scale adaptation to a climatic regimen which is markedly seasonal, but also highly variable between years in the amount and temporal patterning of rainfall.
The distribution of R. colletti amongst vegetation types is influenced by two sets of environmental factors, both reflecting a gradient in elevation, soil type and vegetation. The primary factors are vegetative cover and height, and the extent and duration of flooding; the secondary set comprises buffalo‐induced features such as the degree of pugging and grazing. These factors are interrelated, and their relative importance to R. colletti varies greatly between seasons.
Feral buffalo appear to exacerbate the harsh effects of the wet and dry seasons. The removal of these animals may ameliorate environmental conditions considerably, both temporally and spatially, resulting m generally higher, more stable and spatially less variable populations of R. colletti .
A wild population of Striped fieldmice was studied for a continuous period of five years in an area of alien Acacio bush about 24 km from Cape Town, South Africa. Mice were live-trapped, marked by toe-clipping and released on a 60-station grid, and also kill-trapped in a separate area. Marked annual fluctuations in the population size were correlated with a 6–8 month summer breeding season. There were also marked inter-annual differences in peak population size. The age of sexual maturity of females was determined from the first pregnancy which occurred at 6–7 weeks old; and of males from the presence of visible spermatozoa in the vas deferens which occurred at about 11 weeks old. Litter size was affected by both the age and the body mass of the female. It appeared that mean survival from birth was only approximately 1.5 months and that survival from first capture was about 1.9–2.5 months. This high mortality appeared to be the major reason for the sharp seasonal fluctuations in population size and may also have been responsible for the interannual differences since marked changes in survival were recorded between some years.
The Four-toed Elephant-Shrew Petrodromus tetradactylus is one of the most widely distributed elephant-shrew species, ranging from Kenya to South Africa, while the Golden-rumped Elephant Shrew Rhynchocyon chrysopygus has a limited distribution, being found only on the north Kenya coast. This paper compares the behaviour and ecology of the two species in Arabukc-Sokoke Forest, Kenya. Compared with Four-toed Elephant-Shrews, Golden-rumped Elephant-Shrews have larger home ranges and maintain lower densities, as predicted from their greater body size. Both species prefer areas with dense vegetation cover, avoiding open areas, but the Four-toed ElephantShrew shows a greater preference for dense thicket areas. Territory size was inversely correlated with dry-season spider abundance in Golden-rumped Elephant-Shrews, and with dry-season ant abundance in Four-toed Elephant-Shrews. Differences in activity patterns, as well as body size, may contribute to niche separation between the two species. Both species appear to be monogamous, with males and females defending overlapping territories. Male Golden-rumped Elephant-Shrews range over slightly larger areas than females, and are more likely to trespass into neighbouring territories. The less specific habitat requirements of Four-toed Elephant-Shrews and their higher densities are probably the two most important factors resulting in their wide distributional range.
The activity patterns of six species of captive elephant shrews {Elephantulus (four species), Macroscelides and Petrodromus) were monitored electronically for periods of 48 h. Individual animals showed some significant differences in activity from one day to the next but generally followed the same pattern of diel activity. Intraspecific differences were observed in eight Elephantulus edwardii and seven Elephantulus myurus but all had a similar overall pattern of activity apart from a possibly diseased E. edwardii and two E. myurus , which had previously been exposed to a high level of human disturbance, and which showed increased nocturnal activity. All species were active, to varying degrees, both day and night. Interspecific differences in activity exhibited a continuum, with different species showing differing periods of peak activity. Differences in the nocturnal/diurnal ratio may be related to the amount of cover in the habitat and the degree of aridity experienced by each species. Significant seasonal differences in activity were noted in two species where sample sizes were adequate to permit their detection.
Résumé
On a surveilléélectroniquement le schéma d'activité de six espéces de rats à trompe en captivité par tranche de 48 h. Individuellement, les animaux présentent quelques différences significatives d'un jour à l'autre mais suivent généralement le même schéma d'activité. Des différences intraspécifiques furent observées chez huit Elephantulus edwardii et sept E. myurus mais tous avaient un schéma d'activités globalement similaire, aF l'exception d'un E. edwardii , peut‐être malade, et de deux E. myurus qui avaient ete auparavant soumis à de grands dérangements, et qui montraient un accroissement de l'activité nocturne. Toutes les espèces étaient actives, à des degrés divers, jour et nuit. Les différences interspécifiques étaient permanentes, les espèces présentant des périodes d'activité maximales diffeareés. Les différences du rapport diurne/nocturne peuvent être mises en relation avec le degré de couvertre de l'habitat et le degré d'aridité aux quels est soumise chaque espèce. On a noté des différences d'activité saisonnières significatives chez deux espèces dont la taille de l'echantillon permettait de les détecter.
Global regressions of ecological population densities on body mass for mammals and for terrestrial animals as a whole show that local population energy-use is approximately independent of adult body mass—over a body mass range spanning more than 11 orders of magnitude. This independence is represented by the slope of the regressions approximating –0.75, the reciprocal of the way that individual metabolic requirements scale with body mass. The pattern still holds for mammalian primary consumers when the data are broken down by geographic area, by broad habitat-type and by individual community. Slopes for mammalian secondary consumers are also not statistically distinguishable from –0.75. For any given body mass temperate herbivores maintain on average population densities of 1.5 to 2.0 times those of tropical ones, though slopes do not differ. Terrestrial animals of all sizes exhibit approximately the same range of population energy-use values. These results agree with those reported for population energy-budgets. It is suggested that rough independence of body mass and the energy-use of local populations is a widespread rule of animal ecology and community structure.
In Senegal, the occurrence of three sympatric species of the genus Mastomys is now well established. Reproductive studies were undertaken on field samples from different biotopes and by laboratory breeding experiments. For the three species the litter size at birth in captivity is lower than the number of embryos recorded from pregnant females in the field. The sex-ratio at birth and weaning is not different from 1/1. The other reproductive characteristics can be summarized for each species as follows M. erythroleucus females, after a 21-day gestation period, give birth to 7.1 individuals, 80 % of which survive to weaning. The mean interval between two successive litters is about 61 days. For M. huberti females, the lengh of the gestation period is about 22 days. The mean litter size is about 6.4 and 72 % of newborn survive to weaning. Sixty eight days separate two successive litters. M. natalensis females, after a 21-day gestation period, produce about 6.5 young individuals every 53 days and only 50 % of them survive to weaning. It seems that the larger distribution of M. erythroleucus, compared to the restricted distribution of the other species could be explained by its greater reproductive performances that allow this species to colonize new habitats faster than the other ones.
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