Primate Survey Raises Question: Are Uganda’s Northernmost Chimps Vanishing?

Boat on the White Nile carrying passengers from Umi to Laropi in north Uganda. The Otzi   Mountains are in the background. Photograph by Yvonne de Jong & Tom Butynski.
A boat on the White Nile carries passengers from Umi to Laropi in northern Uganda beneath the Otzi Mountains in the background. (Photograph by Yvonne de Jong & Tom Butynski)

The magnificient Otzi Mountains tower over the confluence of the Achwa River and White Nile in northern Uganda and are prime primate habitat, but no survey of the primates of the Otzi Mountains has ever been undertaken.

In mid-February 2015—the end of Uganda’s long dry season—we spent four days in the Otzi Mountains on a primate survey. Our main focus was the robust (or common) eastern chimpanzee (Pan troglodytes schweinfurthii). We were particularly interested in obtaining information on the status of this population.

We drove and walked in the Otzi Mountains in search of primates and other animals while frequently stopping to look and listen. By talking to residents we learned which primates occur in the Otzi Mountains and its vicinity, and where the nearest groups of primates might be found.

The White Nile winds like a silver serpent below the Otzi Mountains, in northern Uganda. (Photograph by Yvonne de Jong & Tom Butynski)

Chimpanzees of the Otzi Mountains Appear to Be in Trouble

Much of the Otzi Mountains lies within the Otzi East Central Forest Reserve. Otzi East covers an area of 188 km², ranges in altitude from 760 m to 1667 m above sea level, and is contiguous with South Sudan’s Nimule National Park (410 km²). About half of the Otzi Mountains is covered by forest or woodland, while the remainder is comprised of tall grass, bush, and thicket.

In 1993, staff of the Uganda Forest Department discovered chimpanzees in the Otzi Mountains. Based on data obtained during three brief biodiversity surveys conducted in 1993, 1994, and 1995, this population was estimated at between 20 and 40 individuals. A five-week chimpanzee survey —> Read More