Five antelopes of Amboseli

One thing a visitor from India like me has to constantly remind himself of is that there are no deer in Africa (almost). What you are going to see are antelopes. The difference? One text told me, very unhelpfully, that deer belong to the family Cervidae whereas antelopes belong to the family Bovidae. It took me a little searching to figure that the operative difference is that deer have antlers which fall off every year and are regrown, whereas antelopes have horns which keep growing year after year. Another text defined antelopes for me: all bovines which are not cattle, sheep, goats, buffalo or bison. It is a catch-all term, in other words. No wonder Africa teems with antelopes. They fill every possible ecological niche that herbivores can. They are so successful that they leave space only for just a few other medium-sized herbivores.

We saw the waterbuck (Kobus ellipsiprymnus) only once in Amboseli national park. The featured photo shows the characteristic light stripe on its rump. As the name implies, it is very dependent on water, and comes back to it after ranging afield for a while. When we saw this one, it was not very close to water, but could get there in a half hour or so of human-speed walking. It browses on succulent leaves, shoots, and fruits. That’s probably what limits its range, not coming head to head with a zebra.

One of the largest of gazelles, the Grant’s gazelles (Nanger granti, called Gazella granti in the older literature) were more common. We saw occasional small bunches of Grant’s browsing and grazing and learnt to identify it by two signs. One was the lack of black stripes on its hide, and the other was the patch of white on its rump which starts from a little above its tail. This individual never turned to look at us,so we never got to see whether its muzzle had the distinct white-lined black stripes from eyes to mouth, but an identification was still possible from the body. The elegant shape of the horns can also be used to narrow the possibilities. In the dry season they migrate to areas which are not of interest to wildebeest and zebras, since they can eat plants which are unpalatable to those.

Thomson’s gazelles (Eudorcas thomsonii) were very common in Amboseli. You can tell them from the wide black stripes down the flanks. Even if you just see the rump, you can distinguish them from the Grant’s by the fact that the white patch on its rump starts from below its tail. The Family was quite taken by this elegant gazelle and was surprised when she found that it was the preferred food of cheetahs. We never saw a chase, so never saw the spectacular leaps and turns that the Tommie is capable of. I wonder whether the evolutionary race between the Tommie and the cheetah has spurred each of them to be breed for speed. That would be a version of the Red Queen’s statement in Alice about how one has to run fast to stay in one place.

Our first sightings of the very common impala (Aepyceros melampus) came well inside the park. Although it looks very similar to the Grant’s gazelle, it is instantly distinguishable by the black stripes on its rump, the lack of black and white on its muzzle, and the lyre shaped pair of horns. I thought I mostly saw them in grasslands bordering thickets of forest. This makes sense, since they both browse (usually on softer grasses) and graze on leaves. We saw them in August, which is the middle of the dry season, when they eat more leaves, and so push closer to the forest than otherwise. We saw males briefly engaging horns, otherwise they stuck to eating. There were none of the spectacular leaps which wildlife documentaries are fond of showing. The bunch that you see in the photo above are all males; female impala, unlike female gazelles, have no horns.

The most common antelope in Amboseli has to be the blue wildebeest (Connochaetes taurinus). Large herds can be seen grazing along with zebras in the open plains of the park. How do they feed together without being in competition? It seems that the wildebeest strip the succulent leaves of grass (and are therefore more affected by droughts) and leave the tougher parts of grasses for zebras. Feeding together is advantageous for these two, which are the main prey of lions, because they can depend on each other to give alarms. Gnus have also been seen to respond to alarm calls of baboons. They are extremely high strung, breaking into runs at the slightest sign of an alarm and setting others running. I wonder whether this kind of chronic stress is a major factor in the reduction of its life expectation in the wild to about 20 years, when compared to zoo animals which can live up to 40 years.

I’d expected to see more species of antelopes in Amboseli, but five is not a small number in the season of drought. What was remarkable was how the species have specialized their diets to utilize different parts of the ecosystem. In spite of that, enormous habitat loss in the last 100 years has reduced their numbers so dramatically that advertisements for hunting safaris look pretty shocking.