Washoe, a female chimpanzee believed to be the first non-human to acquire human language, has died of natural causes at the Washington state research institute where she was kept. Washoe, who first learned a bit of American Sign Language in a research project in Nevada, had been living on Central Washington University's Ellensburg campus since 1980. She had a vocabulary of about 250 words. She died Tuesday night, according to Roger and Deborah Fouts, co-founders of The Chimpanzee and Human Communications Institute on the campus. She was born in Africa about 1965. She was taken to the veterinary hospital at Washington State University in eastern Washington on Wednesday for a necropsy. Her memorial will be November 12.