The “tommy” as it is referred to in East Africa, is clearly one of the most successful members of its species. Tommies have adapted to the savanna, where it has filled an available niche for a small, selective, migratory mixed feeder. It remains more drought resistant than other antelopes and is the first to arrive and the last to leave the short-grass plains.
They are buff colored with a white rump and a prominent dark side stripe. They have a white streak on either side of the face from eye to muzzle with a dark streak below. Like most true antelope, Thomson’s have facial and leg glands for territorial marking and species recognition. The facial gland is prominent in adult males. The gland deposits a black, tar like substance on blades of grass which delineate territorial boundaries. These deposits can become marble sized after repeated visits. Their sight and hearing are both well developed.
During the breeding season males establish territories and mate with females within their territory. Males are very territorial and act like a sheepdog as they try to maneuver a female into their territory. One dominant male may have up to 200 females within his harem, and yet an hour later he may have none. Non-breeding males form bachelor herds. Outside the breeding season there is a mixing of the groups.
Survival depends on its ability to avoid capture. They are very nervous and flighty. They pronk (bounce stiff-legged with all 4 legs landing together) when playing or alarmed. This may communicate alarm, give them a better view of predators or may confuse or even intimidate predators.
Flight is their chief defense. Although a Thomson gazelle can run faster (65 mph) than anything but a cheetah, it lacks the endurance. Wild dogs and hyenas, which keep their temperature low while running by panting, can usually out run a tommy. Although built for running, gazelles do not use their speed to full advantage as they will run 200-300 yards then stop and look back at the predator chasing them or else they will run about in a zigzag pattern, rather than trying to put as much distance between themselves and their enemies as possible. By contrast, they approach waterholes very carefully. The main herd halts some 200 yards from the water, and then a few young bucks will rush up to the water’s edge, quickly look around, and then dash back to the herd. This is repeated 2 or 3 times before the herd, finally convinced there is no danger, comes down to drink.
With a gestation period of 5-6 months, tommies may have young twice a year. Such a high birth rate is necessary to help compensate for the high losses to predators. Thomson’s gazelle breed seasonally so that births coincide with grass growth in spring after the long rains and in winter after the short rains. When first born, the young hide in the grass and underbrush until they are strong enough to run. When they can run fast enough to keep up with their mothers the two will rejoin the herd. |
