Alarming decline of West African chimpanzees in Côte d'Ivoire

Côte d'Ivoire is thought to be one of the final strongholds of the endangered West African chimpanzee ( Pan troglodytes verus). In a recent assessment of their conservation status, Côte d'Ivoire was estimated to support between 8,000 and 12,000 individuals, accounting for almost half of the remaining world population [1]; however, this estimate was based primarily on a nationwide chimpanzee survey that was conducted in 1989–1990 [2]. Since then, information on chimpanzee abundance and distribution within this region has been sparse. To update the status of chimpanzees in Côte d'Ivoire and evaluate their population trend, we repeated the 1989–1990 survey. Our results show that there has been an alarming decline in chimpanzee numbers, and that urgent action is required to prevent them from disappearing entirely.