We have been witnessing the changing of seasons in which the vibrant green of summer is slowly but surely giving way to the drier tawny winter. This seasonal change is no more evident than early in the morning when the longer autumn nights lift and provide us with beautifully still misty conditions.
In these early May mornings we hear a sound that continues throughout the day – the rutting sound of impala. The scientific name of the impala is Aepyceros Mellampus, which is derived from the Greek words aipos meaning “high”, and ceros, meaning “horn”. The second part, mellampus, is also Greek and is derived from the words melas, meaning “black”, and pous meaning, “foot”. It then means, literally, “the antelope with high horns and black feet”. During the rut we hear the impala rams vocalizing and their “roaring “and snorting sounds can be heard day and night, as often as 200 times per hour. The “roaring” sounds encourage oestrus in females, leading to synchronised ovulation, mating, and births. These sounds are often confused with that of predators, to the extent to which one of my guests was convinced she heard a lion until an impala came crashing through the bush making the “roaring” sound!
During this time impala rams lose all interest in feeding or looking out for predators. Instead the ram will focus mainly on keeping females in his particular area. He is also so busy mating as well as chasing other bachelors away so he hardly has time to eat or to groom himself. The number of ticks on his body doubles and he loses condition really quickly. This weakens him, giving his competitors the opportunity they need to push him out and get some of their genetics into the mix. During the height of the rut, dominant rams will sometimes hold their territory for as little as 8 days before being pushed out by a stronger challenger which then takes charge. The ram which has been deposed will not just slump his head in defeat; instead, he starts feeding and conditioning himself until he is ready to compete for his herd again.
The dominant rams will dispatch any competition, forcing the losers into bachelor herds. The noise of the rut can be heard for long distances as the winners proclaim their territories with snorts and growls and chase the other rams out. The victorious ram then takes charge of the herds of females and attempts to mate with as many as possible. The ram will never mate with the same female more than once. It truly is an incredible to see how these animals interact and watch how these impala rams become almost fixated on their females. It is an exhausting time for the impalas and rams are usually killed by predators during May, because their attention is distracted by the fighting. I would argue that significantly more impala rams are killed than females. It was just the other day that Saseka (our local female leopard) killed an impala ram just outside camp.
In June the craziness begins to abate and the females settle down to a restful pregnancy and then give birth in December just as the rains start. May is a lovely time of the year and very entertaining thanks to the impala.
Report and images by ranger Matthew