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Pup retrieval in the African bush Karoo rat

100%

Pillay N., Willan K., Wolhuter W.

Acta Theriologica

1993

tom 38

nr 3

Maternal retrieval of 87 young representing 42 litters of the African bush Karoo rat Otomys unisulcatus F. Cuvier, 1829 was studied in the laboratory. All 17 females studied retrieved young by nipple-clinging, but ten females also mouth-carried the young in 45 out of 93 trials. Unlike nipple-clinging, mouth-carrying was poorly developed, as young were carried by various parts of the body in a non-stereotyped manner. Mouth-carrying in otomyine rodents is unusual; all other species previously studied use nipple-clinging exclusively. Mouth-carrying in O. unisulcatus can be interpreted in two ways: (1) Nipple-clinging probably evolved in the ancestral otomyines where it reduced the risk of predation on young in unprotected nests. O. unisulcatus occupies well-protected stick lodges where young are not very vulnerable to predation. Hence, the selective advantage of nipple-clinging in O. unisulcatus may be less than in the ancestral otomyines, and it is possible that mouth-carrying may replace nipple- clinging. (2) Alternatively, mouth-carrying may represent merely an experimentally induced response.

Refuge microclimates of rodents: a surface nesting Otomys unisulcatus and burrowing Parotomys brantsii

67%

Du P. A., Kerley G. I. H., Winter P. E. D.

Acta Theriologica

1992

tom 37

nr 4

We investigated microclimates of the nest of Otomys unisulcatus Cuvier, 1829 and the warren of Parotomys brantsii (Smith, 1834) during two seasons and correlated these with the rodents' physiology. In both rodents' refuges, temperature varied less than ambient temperature (TA). In winter, temperatures in the O. unisulcatus nest at 40 cm below the nest apex, and in Lhe P. brantsii warren 15 cm below the soil surface, were higher than noclurnal TA. In summer, during the hours of highest TA, refuges wore cooler than TA. Vapour pressure (v.p.) in the refuges varied less and was higher than ambient v.p. In the humid refuges, heat loss by conduction rather than evaporative water loss is suggested. The nest of O. unisulcatus, with less temperature variation in winter and lower temperatures in summer, was less dependent ofTA than P. brantsii's warren. The use of these refuges therefore contributes to the survival of those mesic rodents in a semi-arid region.

Ograniczanie wyników

2 Acta Theriologica

1 Du P. A.

1 Kerley G. I. H.

1 Pillay N.

1 Willan K.

1 Winter P. E. D.

1 Wolhuter W.

1 1993

1 1992

Wyniki wyszukiwania

Pup retrieval in the African bush Karoo rat

Refuge microclimates of rodents: a surface nesting Otomys unisulcatus and burrowing Parotomys brantsii