Henry and I were enjoying the view from the veranda of the Lake Manyara Hotel. Perched atop the escarpment above Lake Manyara National Park, the hotel commanded sweeping views to the east, south, and north. The Park began almost at our feet, a jumble of trees, shrubs and rocks tumbling down a steep 1800 ft (545 m) escarpment to a narrow, irregular plain of forest, woodland, and grassland bordering the shallow muddy waters of Lake Manyara. Beyond stretched the dry, withered vastness of the Maasai Steppe, its occasional hills and dry stream beds obscured by a haze of smoke from dry-season grass fires.

It was 1964. I was a newly arrived U.S. Peace Corps volunteer and Henry was Henry Fosbrooke, old Tanganyika hand and conservator, Ngorongoro Conservation Area. He was driving me to Ngorongoro where I was to take up my duties as assistant conservator (forests). While Henry finished drinking his tea, I gazed over the park. Twenty-five miles long, it was only a few miles wide, and much of this was steep, rugged escarpment. This made me wonder what was important about the park besides a striking view. “Tree-climbing lions,” Henry stated, setting down his tea cup with a forceful clink. “Unique to this park; the only place in Africa where lions climb trees.” (Note: since then, populations of tree-climbing lions have been found elsewhere, including Ngorongoro, Tarangire, and the Serengeti in Tanzania as well as Queen Elizabeth National Park in Uganda.) Beckoning for a waiter to bring the bill, he added, “There also are rather a lot of elephants.” That did it: I would visit the park the first chance I got.

Lake Manyara National Park is a good example of how the escarpments, lakes, and volcanic highlands of East Africa’s eastern rift valley have influenced the region’s biological diversity, not to mention its scenery.

At 123 sq. miles (318 sq.km), 70% of them water, the park was small. In comparison, the Serengeti National Park, 55 miles to the west, could contain 46 Lake Manyara National Parks.

Nonetheless, it was ecologically diverse. The combination of rocky escarpment composed of ancient basement system and younger volcanic rocks, large shallow lake, and narrow plain watered by perennial streams and springs has created habitats ranging from closed canopy forest through deciduous woodland and thicket, to open grassland and swamp. Examples of three of the most important habitats follow:

Forest: Fed by springs flowing from volcanic rock at the base of the escarpment, groundwater forest consists of plants that could not grow under the existing rainfall. It also contains grassy glades and swamps. The spring water originates outside the park, from rainfall falling on the forested outer slopes of the Crater Highlands thirty miles away.

Acacia woodlands: haunt of tree-climbing lions. No one knows for sure why they spend so much time resting in trees. The more plausible theories include keeping away from herds of buffaloes and elephants and/or from biting flies. (Another, possibly tongue-in-cheek, suggestion is that the trees are simply easy to climb.)

This raises a question: buffaloes are the principal prey of the park’s lions, so why should lions avoid them? Buffaloes are big, mean, and hard to kill. They can put up a real fight when attacked. Consequently, Manyara lions lead harder lives than their Serengeti cousins, who frequently feast off hyena kills. This probably accounts for their desire to keep clear of buffalo herds until hunger drives them to hunt again.

Grasslands support a large proportion of the park’s animal biomass. One of the more important types is strongly influenced by Lake Manyara in that it occurs on alkaline soils of periodically flooded mud flats. Alkali grassland fluctuates widely in area depending on the level of the lake, but is, nonetheless, heavily grazed by buffaloes, gnus, and zebras.

Large and shallow (max. depth 12 ft or 3.6 m), Manyara, like other rift valley lakes, has no outlet, losing its water only through evaporation. Therefore, its area and depth can vary significantly over time. For instance, in 1961, the lake was so dry it could be crossed in a Land Rover, whereas in 1962 rising waters killed many trees along the shore and forced zebras and wildebeests, the latter then the principal grazers on alkali grasslands, into the woodlands where they were easy prey for lions. This destroyed the wildebeest population, which took several years to return. The lake gives, but can also take away.

The varied habitats of Lake Manyara National Park provide optimal conditions for many species of wildlife: klipspringer and Kirk’s dik dik on the rocky escarpment, impala and giraffe in the woodlands, various waterbirds (at times an estimated two million) on the lake . . . However, none benefit more from this habitat diversity than elephants, which can use them all (except perhaps the lake). They can pull up tussocks of grass, forage branches up to 20 ft (6 m) high, wade into swamps to eat aquatic plants, and even carefully negotiate parts of the escarpment. Therefore, it wasn’t surprising that there were a lot of them in the park.

However, there was another, more ominous, explanation for their high numbers: hunting and loss of habitat to agriculture might be driving elephants into the park. If so, they could become so numerous as to outgrow their food supply. In such cases it’s the trees and shrubs that are most affected. If short on forage, elephants will strip bark and eat the cambium, push trees over to get at out-of-reach foliage , dig up tree roots, and gouge holes into baobab trees to access water stored in their trunks. Thus, the most visible impact of elephant overpopulation is the destruction of forests and woodlands.

Furthermore, this already was happening elsewhere. For instance, in Uganda’s Murchison Falls National Park some 1000 sq miles (2290 sq km) of woodlands would be destroyed by 1969. Worse yet, there were signs of damage to trees in Lake Manyara National Park where many Acacia tortilis (umbrella acacia) trees had been knocked down and/or stripped of their bark.

This led Tanganyika National Parks to ask a young British zoologist, Iain Douglas-Hamilton, to study the situation. Iain spent the next few years identifying individual elephants and studying their behavior. He recorded what they ate and their impact on the vegetation. He learned how to age them and monitor their growth. He recorded births and when one died tried to find out why. He counted them and followed their movements. Large as they were, elephants still were hard to spot in areas of dense vegetation, so Iain immobilized a few of the big animals, fitted them with radio collars and tracked them from an airplane, which he also used to census their numbers.

And, along the way, he had some exciting experiences. A partial list includes being hospitalized by an encounter with a rhino while on foot in dense bush, being swept downstream from a causeway while trying to cross a river in flood, and, on three occasions having his vehicle bashed up by elephants. As described in Among the Elephants, these incidents were scary enough to make a prospective wildlife biologist choose another career. That said, except for the rhino encounter, it was Iain’s Land Rover that sustained the most damage. Holed, ripped, bent, and lifted by angry elephants, its fenders were crumpled, roof squashed, and windows broken; the big animals sometimes pushed it around like a baby carriage. It’s a wonder the vehicle lasted through Iain’s study. Nonetheless, it did and here are some of Iain’s findings:

(a) Manyara had the densest elephant population of any park in Africa, well over 10 / sq. mile (3.0 / sq km). Elephants dominated the park’s large-mammal biomass (with buffaloes coming in a close second);

(b) Fortunately, the park’s elephants were not completely confined to the park but had access to the Marang Forest Reserve above the escarpment to the southwest. This reduced the chances, at least for the time being, of their numbers overwhelming the food supply;

(c) Nonetheless, Manyara’s elephant population still might someday outgrow their food supply, destroy their habitat, and starve.

Therefore, Iain proposed the acquisition of land owned by European farmers (many of whom were already leaving the country) at the south of the park. This would provide more room for the park’s elephants but also allow them access, across lightly settled land south of the lake, to the Tarangire Game Reserve (now national park) ten miles to the east (Fig. 3).

Over thirty years later, in 2009, Tanzania National Parks finalized this acquisition, providing hope for the future of Manyara’s elephants.

Iain’s Land Rover did not get bashed in vain.