Dhaka, Oct. 2 -- Chief Advisor Muhammad Yunus has expressed deep sorrow at the death of world-renowned zoologist, primatologist, anthropologist and conservationist Jane Goodall.

The Jane Goodall Institute confirmed that she died from natural causes on Wednesday at the age of 91 while in California during a visit to the United States.

She earned global fame through her research into the behaviour and social lives of chimpanzees.

In a condolence message sent from the Chief Advisor's Office on Thursday, Yunus said: "I am deeply saddened by the demise of my dear friend Dr Jane Goodall."

Describing her as an unwavering warrior until her final day, he added: "She dedicated her life to the cause of peace, sustainability, justice and the inte...