To the editor

Your recent editorial, “Primate research faces extinction,” makes two points: that the Japanese macaque, Macaca fuscata, may be an endangered species, and that its use for research purposes by neuroscientists in Japan may be contributing to the danger of extinction. We disagree with both points.

There are two subspecies of Japanese macaques, M. fuscata fuscata, which is found on the Japanese mainland, and M. fuscata yakui, which is found only on the island of Yaku. There were 3,500 individuals of the yakui subspecies remaining in 1996, and the Japanese primatologists labeled this subspecies as being endangered. Presumably because of the scarcity of the yakui subspecies, the 1996 Red List of threatened species classified the Japanese macaque as endangered. In 1998, the Japanese Mammalogical Society agreed that the yakui subspecies was vulnerable, but also pointed out that the more common subspecies, M. fuscata fuscata, had a population of over 100,000 in the wild, and was at no risk. The Japanese macaque was excluded from the endangered classification of IUCN Red List in 2000, although it still remains on the list as 'data deficient.'

Despite the large numbers of wild M. fuscata fuscata in Japan, it is illegal to capture and use them solely for research purposes. However, farmers in Japan view these animals as agricultural pests, and request the local governments to remove them. Japanese researchers, including neuroscientists, use a small proportion of these captured monkeys as research subjects. Those not used for research are killed immediately under the supervision of local authorities.

Despite the availability of monkeys captured as agricultural pests, any wild population may be subject to change for unpredictable reasons. We therefore feel that there is an urgent need for the establishment of breeding colonies that would produce Japanese macaques for research purposes. Because it takes about seven years for newborn monkeys to become sexually mature breeders, however, we estimate that it will take a long time for breeding colonies to be able to supply an adequate number of research monkeys. At present it is crucial that agricultural pest monkeys continue to be made available to Japanese scientists for research.