The Tarangire River has shrivelled to a shadow of its wet season self. But it is choked with wildlife. Thirsty nomads have wandered hundreds of parched kilometres knowing that here, always, there is water. Herds of up to 300 elephants scratch the dry river bed for underground streams, while migratory wildebeest, zebra, buffalo, impala, gazelle, hartebeest and eland crowd the shrinking lagoons. It's the greatest concentration of wildlife outside the Serengeti ecosystem - a smorgasbord for predators – and the one place in Tanzania where dry-country antelope such as the stately fringe-eared oryx and peculiar long-necked gerenuk are regularly observed. During the rainy season, the seasonal visitors scatter over a 20,000 sq km (12,500 sq miles) range until they exhaust the green plains and the river calls once more. But Tarangire's mobs of elephant are easily encountered, wet or dry.

The swamps, tinged green year round, are the focus for 550 bird varieties, the most breeding species in one habitat anywhere in the world. On drier ground you find the Kori bustard, the heaviest flying bird; the stocking-thighed ostrich, the world's largest bird; and small parties of ground hornbills blustering like turkeys. More ardent bird-lovers might keep an eye open for screeching flocks of the dazzlingly colourful yellow-collared lovebird, and the somewhat drabber rufous-tailed weaver and ashy starling – all endemic to the dry savannah of north-central Tanzania.

A million wildebeest... each one driven by the same ancient rhythm, fulfilling its instinctive role in the inescapable cycle of life: a frenzied three-week bout of territorial conquests and mating; survival of the fittest as 40km (25 mile) long columns plunge through crocodile-infested waters on the annual exodus north; replenishing the species in a brief population explosion that produces more than 8,000 calves daily before the 1,000 km (600 mile) pilgrimage begins again.

Tanzania's oldest and most popular national park, also a world heritage site and recently proclaimed a 7th world wide wonder, the Serengeti is famed for its annual migration, when some six million hooves pound the open plains, as more than 200,000 zebra and 300,000 Thomson's gazelle join the wildebeest’s trek for fresh grazing. Yet even when the migration is quiet, the Serengeti offers arguably the most scintillating game-viewing in Africa: great herds of buffalo, smaller groups of elephant and giraffe, and thousands upon thousands of eland, topi, kongoni, impala and Grant’s gazelle.

The spectacle of predator versus prey dominates Tanzania’s greatest park. Golden-maned lion prides feast on the abundance of plain grazers. Solitary leopards haunt the acacia trees lining the Seronera River, while a high density of cheetahs prowls the southeastern plains. Almost uniquely, all three African jackal species occur here, alongside the spotted hyena and a host of more elusive small predators, ranging from the insectivorous aardwolf to the beautiful serval cat.

But there is more to Serengeti than large mammals. Gaudy agama lizards and rock hyraxes scuffle around the surfaces of the park’s isolated granite koppies. A full 100 varieties of dung beetle have been recorded, as have 500-plus bird species, ranging from the outsized ostrich and bizarre secretary bird of the open grassland, to the black eagles that soar effortlessly above the Lobo Hills. As enduring as the game-viewing is the liberating sense of space that characterises the Serengeti Plains, stretching across sunburnt savannah to a shimmering golden horizon at the end of the earth. Yet, after the rains, this golden expanse of grass is transformed into an endless green carpet flecked with wildflowers. And there are also wooded hills and towering termite mounds, rivers lined with fig trees and acacia woodland stained orange by dust.

Popular the Serengeti might be, but it remains so vast that you may be the only human audience when a pride of lions masterminds a siege, focussed unswervingly on its next meal. Size: 14,763 sq km (5,700 sq miles).Location: 335km (208 miles) from Arusha, stretching north to Kenya and bordering Lake Victoria to the west.

Stretching for 50km along the base of the rusty-gold 600-metre high Rift Valley escarpment, Lake Manyara is a scenic gem, with a setting extolled by Ernest Hemingway as “the loveliest I had seen in Africa”.The compact game-viewing circuit through Manyara offers a virtual microcosm of the Tanzanian safari experience. From the entrance gate, the road winds through an expanse of lush jungle-like groundwater forest where hundred-strong baboon troops lounge nonchalantly along the roadside, blue monkeys scamper nimbly between the ancient mahogany trees, dainty bushbuck tread warily through the shadows, and outsized forest hornbills honk cacophonously in the high canopy.

Contrasting with the intimacy of the forest is the grassy floodplain and its expansive views eastward, across the alkaline lake, to the jagged blue volcanic peaks that rise from the endless Maasai Steppes. Large buffalo, wildebeest and zebra herds congregate on these grassy plains, as do giraffes – some so dark in coloration that they appear to be black from a distance. Inland of the floodplain, a narrow belt of acacia woodland is the favoured haunt of Manyara’s legendary tree-climbing lions and impressively tusked elephants. Squadrons of banded mongoose dart between the acacias, while the diminutive Kirk’s dik-dik forages in their shade. Pairs of klipspringer are often seen silhouetted on the rocks above a field of searing hot springs that steams and bubbles adjacent to the lakeshore in the far south of the park.

Manyara provides the perfect introduction to Tanzania’s birdlife. More than 400 species have been recorded, and even a first-time visitor to Africa might reasonably expect to observe 100 of these in one day. Highlights include thousands of pink-hued flamingos on their perpetual migration, as well as other large waterbirds such as pelicans, cormorants and storks. Size: 330 sq km (127 sq miles), of which up to 200 sq km (77 sq miles) is lake when water levels are high.Location: In northern Tanzania. The entrance gate lies 1.5 hours (126km/80 miles) west of Arusha along a newly surfaced road, close to the ethnically diverse market town of Mto wa Mbu.