Over the next month we will often have guest coming to us big eyed and excited asking if there is a lion or predator close as they heard a weird roar like sound. If there is no lions around there is a simple explanation for this.
It is that time of the year where the Impala rams start making a very impressive “roaring” sound. This is called “RUTTING” . This normally happen in late summer to early autumn. The sound is very unique among our antelopes. The rut evolved as a vocal means of advertising and intimidating rivals. During rutting season males become so involved fighting with other males that they forget/get distracted from feeding and sometimes it becomes so intense that they starve. They pursue females so vigorously with necks outstretched , heads low an mouths open while bellowing a “roar” This goes on all day and night – especially moonlight nights. Because so much energy is used a male soon looses condition and is easily displaced by younger males from Bachelor groups. This process may repeat itself a few times during rutting season – lasting about 8 weeks- insuring a good influx of genes into the breeding pool. The month of May is the peak season for Rutting and by this time the males cavorting has induced the females to come into oestrus. This is a very short lived period for the impala ewes. And within a 3 week period all the females will have been mated with. And by late November early December Impala lambs are born.
There is a long told myth that impalas are able to hold back/delay the birth of their young. This is DEFINATELY NOT the case. Later births in areas with poor nutrition are caused by later conception. A full-term foetus of any kind needs to be evacuated from the birth canal lest it is no longer fits. An animal cannot arrest the growth of a foetus. Some ewes will reabsorb foetuses during unfavourable conditions but this takes place very early on in the pregnancy. Others may abort and these carcasses are seldom found due to scavengers.
References: Game Ranger in your Backpack- Megan Emmet & Sean Patrick
Beat about the bush- Trevor Carnaby