ScienceShot: Desert Elephants Trek Long Distances to Survive

Elephants have outsized needs for food and drink, consuming a minimum of 100 liters of water and 100 kilograms of vegetation daily. Yet a small population of 350 jumbos manages to survive in the harsh Gourma region of Mali, south of the Niger River, where temperatures spike to 50°C, and vegetation is sparse. Rainfall, too, is minimal, with an average annual accumulation of 110 mm in the north, and 600 mm in the south. To find out how the elephants manage to live in this extreme environment, researchers attached GPS collars to nine of the animals (four females in four separate herds, and five randomly selected males) and tracked their movements for 2 years. The data revealed that the Gourma elephants traverse a vast home range of 32,000 square kilometers—the largest range recorded for elephants—in their search for food and water. Indeed, the Gourma elephants' range covers an area 150% larger than ranges reported for desert elephants in Namibia, the researchers report this month in Biological Conservation. "They have a truly stressful life," says Jake Wall, a graduate student in geography at the University of British Columbia, Vancouver, Canada, who led the study, "and their giant range reflects that." The elephants follow a circular route through the desert, heading south at the beginning of the rainy season in April or May, and returning north later in the year apparently in search of specific plants. Surprisingly, the male and female elephants journeyed on such different routes that they shared only a quarter of their ranges. The Gourma elephants are believed to be the last of the herds that once ranged across northern Africa and into the Atlas Mountains. The study's findings may help conservationists, the scientists say, as the elephants face new pressures from climate change and human settlements.

See more ScienceShots.

Posted in Plants & Animals