AI-based satellite survey offers independent assessment of migratory wildebeest numbers in the Serengeti

Journal article

The Great Wildebeest Migrationin the Serengeti-Mara ecosystem is a globally iconic wildlife phenomenon that supports the health and biodiversity of the region by supporting predator populations, regulating herbivore densities, and driving nutrient cycling. This study presents the first AI-powered satellite survey, using two deep learning-based models (U-Net and YOLOv8) to detect and count wildebeest over more than 4,000 km² across two consecutive years in August 2022 and 2023 with F1 scores reaching 0.830 (Precision: 0.832, Recall: 0.838). The satellite-based results show fewer than 600,000 individuals—approximately half the widely cited estimate of 1.3 million wildebeest, which has remained largely unchanged since the 1970s. While some variation may arise from differences in spatial and temporal coverage between survey methods, the satellite approach employs rigorously validated AI models with demonstrated accuracy. Rather than undermining previous methods, this discrepancy underscores the importance of using independent and complementary monitoring tools to refine population estimates and improve our understanding of wildebeest movement dynamics.

Authors: Duporge, I; Wu, Z; Xu, Z; Gong, P; Rubenstein, D

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Oxford University Press
• Journal: PNAS Nexus
• Volume: 4
• Issue: 9
• Article number: pgaf264
• Publication date: 2025-09-09
• Acceptance date: 2025-07-18
• DOI: 10.1093/pnasnexus/pgaf264
• EISSN: 2752-6542
• ISSN: 2752-6542
• Language: English