Nearly a quarter of the world’s primate species are endangered by human activities, according to the World Conservation Union. The group — which is composed of 10,000 scientists, several hundred of whom are meeting in the U.S. this week to discuss the problem — says 50 of 600 primate species are critically endangered, while 88 others are threatened to a lesser degree. For example, bonobos, which live only in the Democratic Republic of the Congo, are caught in the middle of a war that is splitting their habitat in half and driving some hungry refugees to kill them for meat, says Gay Reinartz of the Milwaukee Zoological Society.