The Meaning of Monkey Talk

Krak! Hok! Boom! These might sound (1)_____ random noises to us, but to a species of monkey living in Ivory Coast, they (2)_____ a very specific meaning. During (3)_____ studies of the Campbell’s monkeys in the Tai National Park, naturalists (4)_____ that when the monkeys spotted a leopard on the prowl, they would cry "Krak!" to (5)_____ other members of their group of the danger. A hok, by (6)_____, alerted other monkeys that a crowned eagle was circling overhead. Boom seemed only to indicate that a branch had broken (7)_____ a nearby tree. What particularly intrigued the researchers, however, was the fact that the creatures weren’t just (8)_____ certain sounds to certain events, but seemed to have developed a kind of syntax. Sometimes, for instance, a monkey would add an oo sound to one of the above-mentioned noises, to suggest a(an)(9)_____ but more general threat: so krak-oo would mean that there was danger, but not (10)_____ from a leopard. The language of the Campbell’s monkeys may be "the most complex example of ‘proto-syntax’ in animal communication known to date", the researchers told.