Separate groups of monkeys have different calls that might be the simian version of local dialects. Now Nobuo Masataka of Kyoto University in Japan says the differences can be a response to the demands of the local environment.
Masataka and two colleagues recorded and analyzed the calls of two groups of Japanese macaques originally from the southern Japanese island of Yakushima. One group was removed from the island in 1956 and transported more than 400 miles to Ohirayama in central Japan, where they have lived partially wild ever since. The Ohirayama macaques' "coo" calls, which the animals use to keep track of each other while foraging, were a third of an octave lower on average than those of the macaques that remained on Yakushima.
Since the two groups are genetically identical, Masataka suspects that the dialects are behavioral adaptations. The Yakushima group lives in a temperate forest, while the Ohirayama ...
