British primatologist Jane Goodall, who transformed the study of chimpanzees and became one of the world's most revered wildlife advocates, has died at the age of 91, her institute announced Wednesday.

Goodall "passed away due to natural causes" while in California on a speaking tour of the United States, the Jane Goodall Institute said in a statement on Instagram.

In a final video posted before her death, Goodall, dressed in her trademark green, told an audience: "Some of us could say 'Bonjour,' some of us could say 'Guten Morgen,' and so on, but I can say, 'Hoo-hoo-hoo-hoo-hoo-hoo-hoo! That's 'good morning' in chimpanzee.'"

Tributes poured in from across the conservation world.

"Dr. Jane Goodall was able to share the fruits of her research with everyone, especially the youngest, and to change our view of great apes," Audrey Azoulay, director general of UNESCO, told AFP, adding Goodall had supported the agency's conservation work.

"My heart breaks at the news that the brave, heartful, history-making Jane Goodall has passed," actress Jane Fonda said on Instagram. "I loved her very........

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