From John Hawks comes distressing news of a 90% decline in headcount of chimpanzees from Côte d’Ivoire, published in the latest issue of Current Biology. The paper, “Alarming decline of West African chimpanzees in Côte d’Ivoire,” is authored by some familiar names. One that I quickly recognized is Christophe Boesche, who captured videos of chimpanzee nut cracking behavior.
The team conducted a survey of the chimpanzees and found only 800 to 1,200 individuals, which is a significant drop from the down 8,000 to 12,000 individuals counted in 1989-90. The drop in chimpanzees correlates Côte d’Ivoire’s 50% growth human population sizes. With the increased human footprint comes more hunting and deforestation, driving chimpanzee populations down.
In 8 of the 11 survey sites, researchers found significantly fewer chimp nests than had been found in 1989-90. In Marahoué National Park, study co-author Campbell found only one nest, versus 234 in 1989-90. The only site that did not experience a decline in population is the Taï National Park, a UNESCO World Heritage site that has benefited from intensive research and conservation efforts. The Taï numbers suggest that the apes’ numbers respond to stable conservation efforts.
Our collective knowledge of west African chimps is far less than the east African chimp populations. With recent findings, like the 4,300 years of continuous nut cracking behavior among these populations, we’ve only begun to understand the depth of their behaviors and abilities.
- Campbell G, Kuehl H, Kouamé PN, Boesch C. 2008. Alarming decline of West African chimpanzees in Côte d’Ivoire. Current Biology 18, R903-R904. DOI:10.1016/j.cub.2008.08.015