Female nesting behaviour, pup growth and ontogeny in Brants' whistling rat(Parotomys brantsii)

This study examines aspects of the nesting behaviour of Brants' whistling r at Parotomys brantsii, a medium-sized rodent indigenous to southern Africa. In the semi-arid regions in which it occurs P. brantsii breeds opportunist ically, modifying its breeding period in relation to rainfall. Within a win ter rainfall area, females produced up to four litters of three to four you ng during the winter-spring period following a gestation period of c. 38 da ys, with females showing a post-partum oestrus. The behaviour of females wa s modified by the birth of their pups, after which they spent extended peri ods underground,. interspersed with bouts of food-collecting activity. With the emergence of pups above-ground, females increased their vigilant activ ity. At 5 weeks pups had developed all the important behavioural characteri stics of adults, such as creating their own overnight food stores, collecti ng nesting material and defending st warren area against conspecifics. This was also the age at which the young dispersed from their natal nest area a s well as the time at which females could reach sexual maturity, despite ph ysical immaturity. The high reproductive output of female P. brantsii, as w ell as the rapid ontogeny of their young, compared to other otomyine rodent species, may represent an adaptation for maximizing reproductive potential in the semi-arid areas they inhabit.