Showing papers by "R. J. van Aarde published in 1984"

Adaptations in three species of large mammals (Antidorcas marsupialis, Hystrix africaeaustralis, Hyaena brunnea) to arid environments

Abstract: Adaptations in the springbok Antidorcas marsupialis, porcupine Hystrix africaeaustralis and brown hyaena Hyaena brunnea to arid environments are discussed. Springbok evolved in the arid west of southern Africa. The proximate factor triggering the onset of oestrus is improved nutrition following rainfall and adaptations have evolved to ensure the success of year-round opportunistic breeding. The porcupine can also breed throughout the year but in the Karoo with its dry cold winters, young are only born in warmer wetter months. Following a gestation period of 93 days and lactation anoestrus lasting 120 days, the female porcupine has evolved a special adaptation whereby she will only conceive during the third to seventh oestrous cycle following the end of lactation. This period may be shortened or lengthened thereby enabling her to adjust to climatic conditions in an unpredictable arid environment. The brown hyaena is well adapted to living along the Namib coastal region where severe extremes in temperature ...