The Great Rift

The following is a redacted and modified excerpt from the first part of the “Great Rift”, a BBC Earth documentary series, narrated by Michael Gunton. I have interspersed this with the occasional factoid from Wikipedia (in blue text to easily distinguish them). It’s a fabulous documentary about an extraordinary part of this globe. (You can find the film trailer embedded at the bottom of the transcript).


 

Africa’s Grand-Canyon equivalent formed 13 million years ago, cracking the earth’s crust along the entire east coast of the southern part of the continent. It is lined by volcanic mountains all along and supports some of the most unique creatures on earth.

The highly sociable Gelada Baboon is the highest dwelling primate —an Old World monkey found in the 4,500-metre Ethiopian Highlands. The Giant Mole Rat emerges from its burrow only at dusk and dawn — scurrying back just as quickly as it emerged but with a mouth-full of grass — evading its nemesis, the Ethiopian Wolf. The Gelada Baboon and the Giant Mole Rat are as neighbours from opposite sides of the “street”, that have never met. They are separated by the great rift.

On Ethiopia’s northern most margin of the rift, in the Danakil Depression, lies Erta Alè. This geological infant is Africa’s most active volcano and the world’s only permanent lava lake. In contrast, further south stands one of the oldest volcanos, the 4-mile high snow-covered peaks of Kilimanjaro. Kilimanjaro is one of a long-chain of volcanic mountains along the Rift-Valley.

The valley, as its name implies, lies between two rifts (east and west) enclosing a central plateau. Here, Mount Kenya is endowed with unique alpine plants only to be interrupted by sudden squalls that bring a cover of snow. Only here can you find the Highland rock Hyrax. The Rock Hyrax is a rabbit-like mammal that has evolved exceptionally dense fur. And it has toes, teeth, and bones similar to the type seen on an elephant.

The Rock or Cape Hyrax is a medium-sized (~ 4 kg) terrestrial mammal, superficially resembling a guinea pig with short ears and tail. The rock hyrax is found across Africa and the Middle East, in habitats with rock crevices in which to escape from predators. Hyraxes typically live in groups of 10–80 animals, and forage as a group. Their most striking behaviour is the use of sentries: one or more animals take up position on a vantage point and issue alarm calls on the approach of predators. The rock hyrax has incomplete thermoregulation, and is most active in the morning and evening, although their activity pattern varies substantially with season and climate. Over most of its range, the rock hyrax is not endangered, and in some areas is considered a minor pest. In Ethiopia, Israel and Jordan, they have been shown to be a reservoir of the leishmaniasis parasite.

The Rock or Cape Hyrax is a medium-sized (~ 4 kg) terrestrial mammal, superficially resembling a guinea pig with short ears and tail. The rock hyrax is found across Africa and the Middle East, in habitats with rock crevices in which to escape from predators. Hyraxes typically live in groups of 10–80 animals, and forage as a group. Their most striking behaviour is the use of sentries: one or more animals take up position on a vantage point and issue alarm calls on the approach of predators. The rock hyrax has incomplete thermoregulation, and is most active in the morning and evening, although their activity pattern varies substantially with season and climate. Over most of its range, the rock hyrax is not endangered, and in some areas is considered a minor pest. In Ethiopia, Israel and Jordan, they have been shown to be a reservoir of the leishmaniasis parasite. [Wikipedia]

Here, too, one may catch sight of the Augur Buzzard, while a Giant Ostrich Lobelia, growing at an altitude of 4,000 metres, attracts high-flying sunbirds with its rich supply of nectar. From there, one may need to descend the 1000 metres or so to intercept the fiercely territorial Side-striped Chameleon, like a solar panel, bathing at exact right angles to the sun’s rays to heat its core body by 30 degrees Celsius within minutes.

The Side Striped Chameleon ranges from East Africa including Ethiopia, Kenya, Somalia, southern Sudan, Tanzania, Uganda, and north-eastern Congo (Zaire). (Wikipedia)

The Side Striped Chameleon ranges from East Africa including Ethiopia, Kenya, Somalia, southern Sudan, Tanzania, Uganda, and north-eastern Congo (Zaire). [Wikipedia]

Forty miles to the west of Mt. Kenya, at 2 ½ miles above sea-level, the Aberdare Mountains are host to the Serval, a medium-sized black wild cat found only in Africa. At lower altitudes they also come in a spotted variety. Elephants are also here. Distinct from most other herbivores, elephants can process almost any plant. This has endowed them with the freedom of migration to and from Mt Kenya. Thanks to hunting however, they are now restricted in their travels. But the impossibly shy Mountain Bongo is one of only one hundred individuals of a secretive antelope that spends the day in dense shady forest, away from this human pressure.

African servals are small, slender cats with long legs, a lean body, short tail, and a small head. Their extra-long neck and legs give them the nickname "giraffe cat." Servals have a coat that is tawny with both black lines and spots, while their belly is a soft white. They top out at 40 pounds (18 kilograms) yet have the largest ears of any cat. Just how big are those ears? If we had ears in the same proportion to our head as servals do, they would be the size of dinner plates!

African serval (“giraffe cat”) is a small (max. 18 kg), slender cat with long legs, a lean body, short tail, a small head but the largest ears of any cat. [Image and text: Wikipedia]

Further on is Mount Soussia, with its 500-metre steep cliffs and grassy crater forming a miniature of the valley. This is where the Maasai, a Nilotic (Upper Nile and tributaries, where most Sudanese Nilo-Saharan-speaking people live) ethnic group of some 500 families of semi-nomadic people of Kenya and northern Tanzania, live. They are among the most well-known of African ethnic groups due to their distinctive customs and dress, and because home is near the many game parks of East Africa.

With a 6-month dry season and no permanent streams or lakes, the Maasai — whose familial wealth is measured in head of cattle — need to keep a constant supply of drinking water. To do this, they have developed a system of metal pipes which condense steam from volcanic vents. There is a unique circular mote, enclosing a larval plateau two-miles across, which is sacred to the Maasai — no hunting or grazing is allowed here.

This region is tunnelled by more than six miles of empty subterranean passages, formed naturally from a single underground larval flow. Baboons, roosting on tree-tops to avoid night-prowling leopards and lions, head into this underground chamber. The “Baboon’s Parliament” is reached only by crossing the largest colony of Mastiff Bats who are on their way out. They are the female bats who have just given birth, flying out to feed for the night. Their pups remain packed tightly together for warmth. The females catch insects and return home to roost. Mum tracks down her infant by memory of location, the sound of the baby’s one-in-a-million voice, and its own unique scent. They are mammals — they depend on mum’s milk. And the baboons leave the cave at dawn.

The 500-metre sheer cliffs of Mount Ololokwe, where high winds rise from the valley below, are loitered by the Rüppell’s Griffon Vulture, The Rüppell’s Vulture, having confirmed evidence of flight at an altitude of 11,000 metres (36,100 feet) above sea level, is considered the world’s highest-flying bird. They thrive in the Rift Valley because steep valley walls create fast up-draughts (thermals) that help them soar to seven miles high with scarcely a wing flap. And nothing escapes them. The pecking order is clear to anyone who watches them feed off a carcass.

Rüppell's Vultures are creatures of the more arid and mountainous areas of Africa: particularly semi-desert and the fringes of deserts. They roost on inaccessible rock ledges if these are available, or in trees, usually Acacia. When thermal updrafts start to develop enough lift, about two hours after sunrise, Rüppell's Vultures leave the roost and begin to patrol over the plains, using their exceptionally keen eyesight to find large animal carcasses, or carnivores which have made a kill. They will wait, several days if necessary, until a carnivore leaves a carcass. They have been known to take live prey on occasion, but this is rare. This was confirmed after the unfortunate bird had been sucked into an airplane engine whilst flying over Abidjan, Côte d'Ivoire, at that altitude. This species has a variant of the hemoglobin alpha-D subunit which has a high affinity for oxygen. This protein allows these remarkable birds to breathe efficiently despite the low partial pressure in the upper troposphere -- where humans would normally pass out. (Wikipedia)

Rüppell’s Vultures are creatures of the more arid and mountainous areas of Africa: particularly semi-desert and the fringes of deserts. They roost on inaccessible rock ledges if these are available, or in trees, usually Acacia. When thermal updrafts start to develop enough lift, about two hours after sunrise, Rüppell’s Vultures leave the roost and begin to patrol over the plains, using their exceptionally keen eyesight to find large animal carcasses, or carnivores which have made a kill. They will wait, several days if necessary, until a carnivore leaves a carcass. They have been known to take live prey on occasion, but this is rare. This was confirmed after the unfortunate bird had been sucked into an airplane engine whilst flying over Abidjan, Côte d’Ivoire, at that altitude. This species has a variant of the hemoglobin alpha-D subunit which has a high affinity for oxygen. This protein allows these remarkable birds to breathe efficiently despite the low partial pressure in the upper troposphere — where humans would normally pass out. [Wikipedia]

Then it’s on to the Serengeti grasslands, one mile above sea-level and home to the world’s greatest game-herds. They border Tanzania’s most active volcano, the Oldoinyo Lengai, where you can climb up its steep slopes to visit the steaming, bubbling top of the crater. To the Maasai, this is the “Mountain of God”.

Ash falls onto the surrounding savannah creating dense fertile soil which is too hard for tree roots but great for grass, supporting the world’s largest herd of wilder-beast. Further south, where the east and west rifts converge, sits the alpine grasslands of the Kitulo Plateau.

Further south, the east and west branches (rifts) converge. Here, alpine grassland of the Kitulo Plateau is decorated by floral displays. “God’s Garden” is serviced by unusual insects: monkey beetle, the mountain Marsh Widow Bird, the Protea Sugar bushes, and the Temples Chameleon. The latter is unique among reptiles as it can swivel its eyes independently, and, lining them up, use its tongue to hit prey every time.

Respite is gained from the cool humidity of Mount Raouway, home to an ancient family of towering hardwood trees. Here, new fauna species are always being discovered. Kipings — genetically related to the baboon —  were first discovered in 2005. They feed from over 100 different plants, but especially from the luscious sticky-orange cucumber fruit. In this they help to disperse its seed, as they rummage and chew. But forest clearing, from farming and fire-wood, has left less than 1000 individuals of Kipings.

North-west of Kapingi’s, between Tanzania and the DRC, lies a vast valley floor lined on its west by volcanic mountains stretching up to 3 miles high — such as the Karunga National Park. The Mountain Gorilla, Africa’s largest and rarest Great Ape, evolved from lowland gorillas soon after volcanoes formed. It is larger and furrier. The fertile volcanic soil greets two metres of annual rainfall with lush forest and this great ape’s fibrous diet is accommodated by extra-large chewing teeth and extra-large jaw muscles. The Silverback (male) protects his mate.

— ♣ —

Featured Image: NASA – Visible Earth, Lakes of the African Rift Valley [Wikimedia Commons].

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