Anyone visiting a watering hole in eastern or southern Africa will discover a full range of herbivores, including the Impala. Its name originates from the Zulu language and translates to “gazelle.”
The medium-sized antelope has two recognized subspecies, the “common” Impala and the larger “black-faced” Impala. They are sexually dimorphic, with males being slightly larger and sporting lyre-shaped horns that can reach 36-inches in length. An adult male can reach up to 36-inches at the shoulder and weigh in at 168-pounds.
Active during the day, the species can jump over 10-feet high and distances greater than 30-feet. Impalas are also famous for springing straight into the air, referred to as stotting.
What Is the Average Lifespan of an Impala?
In the wild, the species has an overall lifespan between 12 and 15 years. There is some evidence that the black-faced Impala reaches the upper end of that range more often than the other Impala subspecies, but further data is needed to establish it as a fact.
In captivity, Impala live to an average age of 17 years. That is the average captive lifespan of both subspecies.
There is no conclusive data that shows that males or females of either species have a longer average life expectancy, either in the wild or in captivity.
The Lifecycle of an Impala
Life for an Impala starts with gestation. A female’s pregnancy lasts for six to seven months. The female gives birth to one calf with each pregnancy.
It is worth noting here that there is a belief that a female can hold off giving birth for up to one month if environmental conditions are less than ideal. That belief is up for debate, as many biologists feel that it is unrealistic for an Impala to delay giving birth for that long.
Impalas are a critical food source for several apex predators. Because of this, females tend to give birth during mid-day, when many predatory animals are resting or are their most lethargic. When contemplating the lifespan of an Impala, it is fair to point out that approximately one out of every two calves will die in the first few weeks due to predation.
Impala calves will suckle between four and six months before they are weened. The young will stay within a nursery group within the female herd for up to one year. At that time, young rams will leave the females while most young ewes join the adult females.
Rams tend to reach sexual maturity at about one year, and the ewes reach maturity around 1.5 years. During the seasons when rains abound, males will become territorial and is when mating will occur.
During the dry season, rams will abandon territories. They will join bachelor groups and wander with the females in search of food. Living in herds is also a survival mechanism that increases overall longevity by providing multiple targets for predators.
Diet and Longevity
Unlike more specialized herbivores, the Impala can graze and browse on leaves or twigs. That varied diet increases the potential longevity of the Impala over herbivores with just a grazing or browsing diet.
Threats to the Impala
The common subspecies of Impala are listed as a “species of least concern” by the IUCN. It is a different story for the black-faced Impala that is considered a vulnerable species. Natural calamities and poaching are the reason for the decline in black-faced Impalas.
Another threat for both subspecies is environmental changes brought on by humans. Destruction of natural habitat is a concern as only 25-percent of wild Impalas reside on protected lands.
Even without the threat of humans, the Impala is an important food source for several predators. Cheetahs, hyenas, leopards, lions, and wild dogs stalk them. The Caracal, jackals, wild dogs, and even eagles will prey on calves and the sick (in some regions, Nile Crocodiles will hunt them at watering spots).
Tick infestation is an issue that the Impala must continuously fight. It is serious enough that they constantly groom, and they also have a symbiotic relationship with the oxpeckers that eats ticks. Tick paralysis can be fatal if the infestation is too much, and the need to groom forces Impalas to lower their guard.
There is enough genetic diversity that the Impala does not suffer health issues from inbreeding or gene bottlenecks. They can carry diseases like Anthrax and transfer it to animals that eat them.
Severe droughts, especially in the natural range of the black-faced Impala, have affected overall longevity and population.
In captivity, Impalas do not face the threat of predation, droughts, or disease.
What Is the Oldest Known Impala?
In the wild, a lack of data and studies limits us to estimates of 17-years. The oldest captive Impala lived for 25.5 years.