Thomson’s Gazelle, Eudorcas thomsonii

Thomson’s gazelle (Eudorcas thomsonii) is also known as a “tommie” and is one of the most well-known gazelle species. Named after Joseph Thomson, Thomson’s gazelle is native to Africa where it is the most commonly found gazelle. It is sometimes considered a subspecies of the red-fronted gazelle, and was previously in the genus Gazella, in the subgenus Eudorcas. Eudorcas eventually became a distinct genus, classifying some species of gazelle within their own genus.

Thomson’s gazelle can have an average height of up to 2.3 feet and males can weigh up to 66 pounds. It can be easy to confuse Thomson’s gazelle with Grant’s gazelle,  as they have similar fur coloration and size. However, Thomson’s gazelles have distinct markings including a thick, black stripe on each side and a white underbelly that never reaches above the tail. In Grant’s gazelle, this white often extends above the tail. The horns are long and slightly curved.

Thomson’s gazelle prefers habitats within the Serengeti areas of Tanzania and Kenya, with plenty of short grass to eat. However, their diet depends on the season and they will migrate to areas with long or dense grass, or wooded areas, during the dry season to forage for clovers, bushes, and foliage. During the wet season, they can be seen grazing in the open on soft, fresh grasses. Because they are so dependent on these shorter grasses, they will follow behind larger grazing animals that feed on longer grasses, waiting for their preferred food to become available.

Mating occurs during the wet seasons, when grass food is abundant. Males, or bucks, will spread out and form territories. Typically, older bucks hold territory while younger males form bachelor groups that are not allowed to enter an established territory. If a young male does enter a buck’s territory, the offender must fight with the buck, although fighting rarely occurs among older bucks. Sometimes, territory boundaries overlap, and if two bucks encounter each other at this “line”, they will mock fight and slowly move away from each other while grazing. This does not constitute a fight for dominance, but a reminder of territory boundaries.

Female Thomson’s gazelle, or does, will form traveling groups as well, and they will usually enter a territory that has abundant resources. Bucks will attempt to herd the females farther into their territory and keep them there, although typically only one remains from the traveling group. If a doe attempts to escape, the buck will chase her and try to herd her back. Sometimes, the female enters the territory of another buck, and this ends the chase with the previous buck, although the new buck will now attempt to herd her into his territory.

Thomson’s gazelles preform typical mating rituals that involve a buck following a doe and performing the flehmen response after she urinates to determine if she is in estrous. After mating, a doe will leave the herd and give birth to a single fawn in the safety of tall grass, typically twice a year. The mother will lick the fawn clean of any afterbirth or other materials, and it is thought she does this in order to give the young her scent, among other reasons. Unlike some species of gazelle, Thomson’s gazelle mothers do not gather in herds, but are able to protect their young alone against small predators such as baboons, which they may head-butt.

Initially, a fawn will remain hidden in the grass, with its mother periodically returning from grazing to nurse it. Young can be nursed up to four times a day, and will venture out for approximately an hour a day once they are able to walk, always accompanied by its mother. At around two months of age, the fawn will stop hiding in the grass, although it will continue to nurse. Soon, the fawn and mother will return to a herd. Female fawns will remain with their mother until the age of one year, and males may do this as well, unless the dominant buck chases it off. Once this occurs, the young buck will join a bachelor group.

Thomson’s gazelle are typically prey to cheetahs, but other predators include baboons, hyenas, leopards, crocodiles, and lions. Because of their small size and long legs, these gazelle can escape at speeds of up to 50 miles per hour. They will also implement a zigzagging pattern in their quick pace, which often allows them to escape their predator. They may also use a method of escape known as stotting, in which the gazelle will leap in the air while bounding in order to show strength and possibly frighten the predator away.

Thomson’s gazelle currently number approximately 550,000, a sixty percent decrease between the years of 1978 to 2005. The decrease has occurred in areas where they are commonly found including the Serengeti and Masai Mara. Major threats include habitat modification, tourism, road development, and fire management. Thomson’s gazelle has been given a conservation status of “Near Threatened” on the IUCN Red List.

Image Caption: Male Thomson’s Gazelle in Serengeti. Credit: Ikiwaner/Wikipedia