The bush Karoo rat Otomys unisulcatus on the Cape West coast

In the Postberg Nature Reserve, coastal Western Cape Province, bush Karoo rats Otomys unisulcatus build dome-shaped stick shelters or lodges, with a mean height of 1,45 m and a mean volume of 0,61 m3, usually with Exomis microphylla var. axyrioides as a supporting shrub. Sticks and twigs utilized are from 10 to 517 mm long, 3,5 mm thick, and with a mean length up to 117 mm per lodge, interwoven to form intricate structures. These are criss-crossed with passages and contain two nests and two latrines each. More than 13 000 sticks can be used to build a lodge; this involves travelling total distances of up to 16,5 km to gather building material. A network of paths interconnects lodges and leads to shrubs providing sticks and food. Most lodges are inhabited by one or two individuals. The species is diurnal and crepuscular

Laboratory and field observations on Zelotomys woosnami (Rodentia: Muridae)

Woosnam’s desert rat, Zelotomys woosnami, occurs in the arid regions of southern Africa. It is sparsely distributed, asocial and nocturnal, and probably utilizes burrows of other rodents although it can dig well. It has a wide food spectrum ranging from seeds to flesh, and is an agile climber. The litter size of 4,7 and the rapid postnatal development are thought to be adaptations to a short breeding season in the summer months, and to capitalize on seasonally-rich resources in a potentially hostile environment. Minimum period between litters was 31 days

Comparative behaviour and ecology of two sympatric mongoose species (Cynictis penicillata and Galerella pulverulenta)

The activity, movements, home range size, habitat selection, social structure, density, pattern of faeces deposition, anti-predator behaviour, diet, and availability and distribution of the main food sources of two mongoose species [the yellow mongoose Cynictis penicillata and the Cape grey mongoose Gaierelia pulverulenta (= Herpestes pulverulentos) in a coastal area of South Africa are compared, Both species were diurnal. Galerella did not use dens, whereas Cynictis never rested outside a den. Total distance moved, home range size and density did not differ between the two species. Galerella frequented bush, whereas Cynictisfrequented open fields. The yellow mongoose was more social than the grey mongoose, but the basic social structure was similar. Faeces of Cynictis were found in large clumps close to the dens, while those of Galerella were more scattered. This parallels the greater constancy of use of the sleeping sites by Cynictis.Rodents (> 90% of Cape grey mongoose diet) were much more abundant in the bush, while availability of insects (main food source for the yellow mongoose) was higher in the open fields. Habitat selection, Ihrough its effects on anti-predator and feeding strategies, might have been the leading factor in the evolution of sociality in herpestids

Climbing behaviour in three African rodent species

The climbing ability and propensity of Thallomys paedidcus, Praomys natalensis and Saccostomus campestrls were studied in the laboratory.  Thallomys was morphologically and psychologically best adapted to arboreal life, although Praomyshad the highest climbing frequency, largely attributable to a greater exploratory tendency. All three species made use of the tail in a prehensile manner, and it was also used as a balancing organ by Thallomys and Praomys. These two species, but more noticeably Thallomys, made use of semi-opposable digits on the hind-feet whilst climbing. Only Thallomys scent-marked branches

Winter activity of bat-eared foxes Otocyon megalotis on the Cape West coast

Diurnal activity budgets of bat-eared foxes Otocyon megalotis in winter (June) at the Postberg Nature Reserve, West Coast National Park, were analysed to determine the influence of environmental factors on their activity. Abiotic factors such as effective temperature, wind speed, cloud cover and rainfall have an effect on prey availability and thermoregulation of the foxes and therefore affect their activity rhythm. Low effective temperature and high wind speed result in more resting and less foraging by foxes. The reverse applies at high effective temperature and low wind speed. No foraging occurred during rain, and only for short periods when the sun shone on overcast days. With the start of pair formation in June–July allogrooming, which was not influenced by abiotic factors, increased. Foxes resumed activity from the same resting sites each day

Dominance and population structure of freshwater crabs (Potamonautes perlatus Milne Edwards)

Although freshwater crabs, Potamonautes spp, are abundant (up to 23 crabs m-2) in southern African freshwater systems and form a major part of the diet of many vertebrates, little is known about their biology. Understanding crab population dynamics and behaviour, for example, is important to understanding their role in the ecosystem more clearly. In this paper we report on dominance in Potamonautes perlatus and test the prediction that larger crabs are dominant to smaller ones, i.e. a linear hierarchy exists and it is size dependent. To understand how this would affect wild populations we also investigated the population structure (sex ratio, size distribution, density and population growth) of a wild population. Using Landau's index of linearity (h) we found three captive groups of P. perlatus to show moderate linearity, i.e. h = 0.9; 0.81 and 0.83. In all three groups the largest individual was the most dominant. There was a significant Spearman rank correlation between dominance rank and size of largest chelae in two of the groups, and a significant Spearman rank correlation between dominance rank and carapace width in only one of the three groups. Densities of crabs in the Eerste River, Western Cape Province, ranged from a mean of 2.89 ±2.11 to 15.57 ± 7.21 crabs m-2. Unexpectedly the size class distribution of the crabs remained unchanged during the year. The lack of a significant increase in the mean size of the crabs can probably be ascribed to a year-round consistency in the availability of refugia for specific/different size classes. Intraspecific aggression, predation and refuge availability are probable strong selection pressures in determining population structures of wild populations of P. perlatus.Keywords: Dominance. linear hierarchy, population structure, refuge availability, rivers, South Afric

Hoarding in four southern African rodent species

The comparative hoarding behaviour of four rodent species,Saccostomus campeslris, Desmodillus auricularis. Tatera brantsii and T. leucogaster was studied under semi-natural conditions after prior determination of the seed preferences of each species.The results are consistent with all available ecological data.  Desmodillus  and Saccostomus are true larder-hoarders, although Desmodillus also scatter-hoards on occasion. The Tatera spp. did not hoard, but frequently covered seeds, a possible primitive form of scatter-hoarding

The bat-eared fox : a prime candidate for rabies vector?

Bat-eared foxes, Otocyon megalotis , are small (3-5 kg) , primarily insectivorous carnivores widespread in the more arid areas of southern and East Africa. For many months of the year they live in nuclear family groups, members of which frequently indulge in affiliative behaviour such as play, allogrooming, and huddling. Physical contact between individuals in any particular group is thus common. In addition, groups are non-territorial and intermingle freely at times when exploiting food-rich patches of clumped prey, e.g. individuals foraging for harvester termites, Hodotermes mossambicus.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Foundation for Research Development. University of Pretoria. University of Stellenbosch.mn201

The coastal Namib Desert as habitat for mammals

The coastal Namib is characterized by low habitat diversity, low primary productivity and adverse climatic conditions, and therefore few primary consumers. These are restricted to favourable habitats, often very localized. The relatively large array of carnivores subsist to a very large extent on food of marine origin, eg seals and seabirds. -from Autho

Book ReviewHandbook of the Mammals of theWorld,Vol. 1 : Carnivores

Edited by D.E. Wilson & R.A MittermeierLynx Edicions, Barcelona. 2009. PriceEuro 160. Hardback. ISBN 9788496553 491African Zoology 45(2): 348–350 (October 2010