A region of Tanzania known as the Northern Circle acts as host to a wildlife show that puts even your wildest dreams to shame. In addition to Serengeti, Lake Manyara, and Arusha National Parks, it encompasses Mt. Kilimanjaro, the Ngorongoro Crater, and Olduvai Gorge (where Mary Leakey discovered the Zinjanthropus Man). Whether you drive into the untamed region by way of cosmopolitan Nairobi, Kenya (a three-hour drive), or fly directly to Arusha (the in-country kickoff point for a tour of the hinterland), you will find unrivaled fauna and geological treasure-troves waiting to greet you.
Nairobi's hotels are as slick and comfortable as Europe's best. Arusha has several swank-looking but poorly run Tanzania Tourist Corporation (TTC) hotels, where you can rest your head in non-noteworthy comfort. But people eager for wildlife do not stay long in Arusha or Nairobi. They go west, where the natural splendors defy any human effort to outdo them.
Photographer Todd Hoffman and I traveled by Land-Rover with Dutch biologist Herbert Prins, who has been studying the buffalo in Lake Manyara National Park for the past four years. We planned to spend a week with him. We spent nearly five. Tanzania's wilderness works on you, absorbs you. Once there, the civilized world drops away, and your interest in stepping back into it gets sapped.
If you don't happen to have a friend doing research in the region, you can link up with Overseas Adventure Travel (OAT) -- a Boston-based agency with a representative in Arusha.
Just 10 miles beyond Arusha, toward Manyara National Park, the vista opens up and hints at splendors to come: Graceful impala leap over tawny grasses; ostriches prance through the dusty bush. Fifty miles farther, the two-lane tarmac road ends, and you are at the mercy of a narrow track cluttered with holes big enough to swallow a hyena. From here on it is a trade-off: rugged riding in exchange for extraordinary gifts of the wild.
The entrance to Manyara is just beyond the village of Mto Wa Mbu (``Mih-too-wam-boo''), where we shopped under banana leaf canopies for cabbages, tomatoes, papaya, and red-skinned bananas. We based ourselves within the Park at Ndala Research Camp, nestled against the Great Rift Wall that stretches the length of Africa. Perched atop this towering escarpment is TTC's Lake Manyara Hotel, where OAT travelers frequently bed down for the night. It boasts a spectacular view of the entire park, and a swimming p ool that attracts overheated people and thirsty baboons.
Manyara has the greatest density of herbivores in the world, including the largest concentration of elephants. The park is renowned for lions that lounge in the flat-topped acacia trees, as well as for exotic and varied bird life. The best spot for taking in this remarkable diversity is the hippo pool, a shallow river at the park's northern end. Here, hundreds of chortling hippos laze and hobnob back-high in the water, their pink-rimmed eyes and ears blinking and twitching just above the surface.
We came here often just before sunset, during that golden time of day when all life seems linked as light and color. North were the soft hues of yellow fever trees in the ground-water forest; south, a scrawl of pink, where thousands of flamingo grazed on Lake Manyara's algae; west, herds of black buffalo, and the escarpment backlit by a setting sun; east, the hippo-filled river bordered by pale grasslands that fed a thousand wildebeest and zebra and stretched wide toward hills.
What makes Tanzania's parks so special is the fact that they are less people-crowded than Kenya's -- where a dozen tour vans are likely to join yours when you stop to watch a pride of lions or a drift of warthogs.
We spent several weeks in Manyara, learning to fit with the rhythm of the wilds, then drove 50 miles northwest to the volcanic highlands. Here stands Ngorongoro Crater, one of the biggest calderas in the world.
No description can prepare you for the peaceable grassy kingdom that sits 2,000 feet below this crater's lushly forested rim. The animal population that inhabits the 100-square-mile crater floor approaches Manyara's in diversity and density. Wild herds, predators, and the domesticated cattle of Masai pastoralists lick water from the glassy lake at the western end of the crater.
After exploring Ngorongoro, we headed farther northwest into the Serengeti Plain toward Ndutu Camp. En route we saw a pack of hyenas ripping apart a gazelle while greedy vultures circled overhead. For all the beauty of this place, there is a fearsome symmetry. Things prey on each other. Carcasses are strewn about, as if to remind you that this is the animals' territory, not yours.
Ndutu is delightful for its bare-bones atmosphere, its no-frills comfort. Trees are scrawnier, land contours less dramatically open, and wildlife more secretive. We arrived at twilight, dined on bush pig, and spent the night. While we slept, an elephant felled the acacia tree outside my room.
The next morning we left the scrub forest of Ndutu and made our way toward Serengeti National Park. Trees became rare, and soon an uninterrupted horizon stretched full circle around us. Brilliant white clouds sank below it like sailing ships at sea. Autumn (springtime in the Northern Hemisphere) is an extraordinary time of year to cross the plain, for it is the season of the Great Migration, when millions of herbivores, trailed by predators, graze their way southeast toward rainy- season grazing grounds . Every direction we turned we saw gazelles and zebra, and more wildebeest than we could begin to count. This primeval spectacle is repeated each June when the animals head northwest again.
After several days on the plain, we bucketed our way back toward Manyara, stopping at Gibbs Farm, southeast of Ngorongoro.
Gibbs is a slice of comfort in the midst of physically grueling Tanzania. In the hills of Karatu and tended by the green thumb of British expatriate Margaret Gibbs and her reliable team of Tanzanians, it is a place where temperatures graciously drop, and a rainbow array of flowers, fruits, and vegetables rises in profusion. The farm, which has an elegantly homey main lodge and dining room, plus 12 comfortable guesthouses, is a jewel of self-sufficiency. In a country where basics, not to mention amenitie s, are difficult to come by, Margaret Gibbs and her cohorts fatten and butcher their own calves and pigs, milk cows, churn butter, and even grow, roast, and grind a savory coffee. There is afternoon tea with scones, and creative dinners that rival the nation's natural wonders.
Unfortunately, Gibbs Farm is an exception in Tanzanian lodging. Tourists who decide to spend all or part of their East Africa wildlife safari in Tanzania should plan to camp or face the fact that hotels here are comparatively run-down. I found the shortcomings bearable because the wildlife is so remarkable and Tanzanians are so friendly. But if good food and hot showers are central to your vacation, you might prefer a Kenyan wildlife safari. It is definitely the road more traveled and has amenities that
usually come with any active crossroads. Practical information
Whether you choose Kenya, Tanzania, or a combination, you can get help planning your trek from Overseas Adventure Travel. OAT offers tours that vary widely in terms of ruggedness and comfort -- from a plush three-week Kenya/Tanzania lodge safari, to a rigorously spectacular two-week Northern Circle walking-trucking tour that calls for sleeping bags and culminates in a five-day climb of Mt. Kilimanjaro (OAT, 10 Mount Auburn Street, Cambridge, Mass. 02138, telephone  876-0533).
Another resource is the East Africa Safari Company. Contact it for tours that are as exciting and exclusive as they are expensive (250 West 57th Street, New York, N.Y. 10107, telephone  757-0722).
For further information contact your travel agent, as the offerings for safaris are plentiful.