Conservationist Dame Jane Goodall, a world-leading expert on chimpanzees, has died aged 91.

Her observations helped to reveal how closely related humans are to chimpanzees. She also worked tirelessly for conservation projects around the world.

Dr Goodall died of natural causes while in California on a speaking tour of the US, according to a statement from the Jane Goodall Institute. It said her discoveries 'revolutionised science' and that she was 'a tireless advocate for the protection and restoration of our natural world.'

The United Nations mourned her loss, stating that she 'worked tirelessly for our planet and all its inhabitants, leaving an extraordinary legacy for humanity and nature.' Greenpeace expressed heartbreak over her passing, calling her 'one of the true conservation giants of our time.'

Naturalist Chris Packham remembered her as a hero, asserting that losing such a visionary at a time when her voice was most needed is a profound tragedy.

Born in 1934, Dr Goodall's fascination with animals began in childhood, leading her to study under noted primatologist Prof Louis Leakey. She made history as the first person to observe tool use among chimpanzees, significantly altering the perception of their intelligence.

Throughout her life, Dr Goodall advocated for animal rights and tirelessly fought against habitat destruction. Her legacy includes the Jane Goodall Institute, which has worked for decades to protect chimpanzees and their environment.

Even close to her passing, Dr Goodall remained active in her advocacy, recently participating in a sold-out speaking event. Her dedication serves as an enduring inspiration for future generations riding the wave of conservation efforts worldwide.