Savanna and the Serengeti Eco Info
Africa's savannas stretch like seas of grass across the dry rolling plains. Once all home to migratory populations of wildebeest, elephant and wandering rhino, savanna wildlife is now limited to roaming the confines of game reserve areas. These habitat restrictions are wearing out the land and gene pool alike, causing weakness and damage to the ecosystem. But some efforts are now being made to remove barriers and re-establish natural habitats.
Of the many African savannas, the Serengeti is most well known for its vast herds of wildebeest, gazelle and zebras. It is also home to one of the highest concentrations of large predators in the world. Here, lions and hyenas seldom go hungry. From the grass-grazing zebras to tall tree-foragers like the giraffe and elephant, each of the Serengeti's wildlife makes the most of all available food sources.
Wildebeest (Connochaetes taurinus):
Almost never without its herd, wildebeest are one of the most distinctive groups on the Serengeti. Each year, over 1 million wildebeest travel in a circular migration according to seasonal rains across the Serengeti plains. Their grazing and trampling of grass allows new grasses to grow, while their waste helps fertilize the dry Serengeti soil. During the heavy rains of April and May, wildebeest move off the central southern plain to the northwest near Lake Victoria. In June, they continue north, spending the dryer months of July through October in the green pastures of Kenya's Maasai Mara Game Reserve. By November, grass has returned to the central Serengeti plains and the herds start heading south, spending December through March once again on the central plains.* Also known as gnu, the grass-eating wildebeest stands about 4 to 6 ft. high and weighs between 350 and 600 lbs. Its natural predators are At night white-bearded wildebeest sleep on the ground in rows; this provides them with the security of being in a group while allowing them
space to run in case of an emergency. (1982 Serengeti pop est. 1.3 million )
African Lion (Panthera leo)
The king-of-the-jungle is actually the king of the savanna. Most African lions live on the open plains. They live in small family units that move with a larger group of up to 40 members. Females do all the hunting, and usually team up when stalking prey. These large, tawny colored felines weigh between 260 lbs. for a heavy female to 575 lbs. for a full-grown male. Sharp, retractable claws and two-inch teeth make the lion an apt killing machine. But just like a house cat, lions love to sleep, play and cuddle. After a hunt, lions will hang around together for several days, keeping cool under trees or chasing one another's tail. Although once lions roamed freely, today the largest populations of these big cats are found in the Tanzania's Serengeti and South Africa's Kruger National Parks. (1982 Serengeti pop est. 2,800)
African Elephant (Loxodonta africana)
African elephants are the world's largest land animals. They stand just under 9 ft. tall and tip the scales at over 13,000 lbs. Elephants live up to 50 years, and go through six sets of teeth during their life. Most live in large, extended family units that can range from six to 70 individuals. When an elephant dies, its family will mourn by staying with the body for a day or so, and then covering it up with branches. Once found throughout the African continent, elephants were decimated by hunters until an international ban on the poaching and trading of elephant tusks went into effect in the 1970s. Today, elephants are mostly found in restricted areas of central Africa, Kenya and Tanzania and national parks in South Africa. This is largely because of shrinking resources for elephant food needs. An elephant can require up to 500 lbs. of grass and 50 gallons of water a day.
Kirk's dikdik (Madoqua kirkii)
A miniature antelope standing around 2 ft. tall, and weighing a mere 11 lbs. , the dikdik grazes on the small shoots of plants, grasses and very low bushes. This tiny deer is easily startled, and is likely to bounce away from predators in a series of erratic leaps. One of the dikdik's best defenses is simply to hide in bushes; it is so small, it is easy to miss. Its name refers to a warning call it makes that sounds roughly like "zdik, zdik."
Gerenuk (Litocranius walleri)
The gerenuk is also known as the gazelle-giraffe because of its long giraffe-like neck. When standing on four legs, it is just over 4 feet tall, but thanks to an evolutionary adaptation, the gerenuk is also able to stand on its hind legs, and extend its forelegs. Standing upright at a towering height of 6'5", it can pluck succulent leaves from between acacia trees' thorny branches.
Topi (Damaliscus lunatus)
Smaller, and less abundant than the wildebeest, this antelope is also commonly found on the Serengeti plains' grassy savannas. Standing from 3 to 4 feet tall, Topi are sleek with fur of a reddish tan. They are strictly grass-eaters, and tend to group in small herds that are considered "closed" because they do not take kindly to newcomers.
Like other regions in Africa, water --either too much or too little, is of great concern to life on the savanna. Migration restrictions worsen this condition as over-grazing and delayed rainy seasons lead to soil erosion, and the potential for flooding. Animal populations are further threatened by poaching and disease. Rinderpest, a cattle disease carried in by foreign settlers has decimated wild and domestic herds twice in the last century.
African Wildlife Foundation
Rainfall and Temperature
Annual Savanna rainfall fluctuates between 20 to 47 inches. A short rainy season kicks off in November as the wildebeest migrate south. In March and May, longer rains come and the wildebeest return north.
The Savanna has a semi-arid climate. Temperatures are moderate all year long, with highs in the mid to upper 80s and lows in the 60s.
Among Africa's many savanna regions, the Serengeti is the best known for its size and the majestic annual migration of thousands of wildebeest. The Serengeti is a vast undulating plain stretching 11,583 sq. miles, from Kenya's Maasai-Mara game reserve south across the boarder to encompass Tanzania's Serengeti National Park. Other rolling grass savannas run through the Sahel region, and can also be found in Southern Africa along side the Namib desert.
Savanna vegetation means grass. Lots of grass. But these aren't tame, back yard blades. For much of the African savanna's wildlife, grass is the key to survival.
Most savannas are dominated by grasses of varying species, depending on the area's rainfall and top soil conditions. Serengeti grasses are called "sward" --a mix of palatable grasses consumed by grazing animals like antelope. Many savanna regions are also dotted with hardy trees like the drought-resistant acacia and the water-conserving baobab. Both have specially designed root systems that allow them to make the most of what little water the region has to offer.
Acacia, whose deep root systems are ideal for semi-arid climates, are among the most common trees found on the Serengeti. Known for its gnarled, thorny bark and velvety leaves, the acacia is mentioned in the Old Testament and is said to have been the raw material used to build Noah's Ark. The tree's feathery leaves protect its bark from dry winds. If it doesn't rain, acacias may not produce leaves. The tree blooms in yellow or white fuzzy flowers. The bark of most acacias produces tanin, which is used in tanning leather; a variety of acacia native to Sudan, acacia senegal, produces gum arabic, used in pharmaceuticals and adhesives.
Baobab (Adansonia digitata)
Also known as the rat tree, or monkey-bread or bottle tree, this is one of the largest trees on the planet. Its trunks are often 50 ft. wide, and it can reach heights of up to 85 ft . The straight long trunk ends in a comparatively few crooked branches. The baobab is completely without leaves in the dry season. Some local legends say that spirits planted the baobab tree upside down, thus accounting for its scraggly appearance in the dry season. The rainy season brings on long, hanging flowers which yield edible "monkey fruit."
Red Oat Grass (Themeda triandra)
Also known as kangaroo grass or bluegrass, this is a tough, bluish-green grass that can grow over 3 feet tall. At the end of the grass's growing cycle, it dries to a golden yellow and sports flattened, fan-like seed pods. While this is one of the most common grasses in the Serengeti, it has very low nutritive value.
Rabbit-Tail Fountain Grass (Pennisetum mezianum)
A tufted grass that grows to about 3 feet in height, the rabbit-tail fountain grass sports blooms in the dry season that look like short, fluffy, purple caterpillars. This grass flourishes in poor, dry soil under full sun.