Upper Grumeti Woodlands

Ecosystem: The Gallery Forest and the Whistling Thorn

The riverine environment is a lush haven of fig, mahogany, date palm, and tamarind trees. Though the river is seasonal, deep permanent pools support resident hippos and crocodiles year-round.

• Avian Brilliance: The canopy is alive with the “harsh calls” of Hartlaub’s and Ross’s Turacos—vivid green and blue birds with striking crimson wings. The lonely cry of the African Fish Eagle frequently echoes over the water.
• Primate Paradise: The forest is home to playful vervet monkeys and large, inquisitive troops of baboons.

In the surrounding woodlands, nature has evolved fascinating defense mechanisms:

• The Whistling Thorn: This acacia produces hollow galls at the base of its thorns, providing “apartments” for ants. The wind blowing across the entry holes creates a distinct whistling sound. In a symbiotic exchange, the ants defend the tree by attacking any browser that tries to eat its leaves.
• Maasai Giraffe (Twiga): These elegant giants dominate the woodlands, feeding on tender acacia leaves. Despite their height, a giraffe’s neck has only seven vertebrae—the same as a human’s. In Swahili, they are called Twiga, the national emblem of Tanzania.

The Great Migration

The migration thunders through the Upper Grumeti twice a year: heading north in July/August and returning south from September to November. The southward journey is especially pronounced, as the herds tend to linger in the lush woodlands for longer periods. Throughout the dry season, a constant stream of wildebeest and zebra can be seen flooding through the acacias in their relentless search for water.