"Staring into the eyes of a chimpanzee, I saw a thinking, reasoning personality looking back," said Jane Goodall in the 2017 National Geographic documentary Jane. The film, crafted from more than 100 hours of previously unseen footage, captures the now world-renowned British primatologist during her work in the 1960s at Gombe Stream National Park in Tanzania.

Though widely viewed as a trailblazer today, back in the initial few months of her stay in Gombe in 1960, Goodall saw herself as "the white ape", an intruder desperate to be accepted and embraced by her long-armed kin.

The breakthrough came one morning after Goodall had "tramped up and down three different valleys in search of chimps but had found none", to quote herself. That's when she spotted an adult male whom she had long known by sight. This time, he didn't run.

David Greybeard was the name Goodall gave the ape with a tuft of distinctive white hair on his chin. The very first individual of his community to have trusted her, David Greybeard led the budding primatologist to her first major discovery about the chimps as toolmakers.

"I watched spellbound as the chimps set off to a termite mound, picked a small leafy twig, and stripped it off its leaves. That was object modification, the crude beginning of tool making," said Goodall, referring to the fact that the chimps used the sticks to get termites out of their tunneled home.

"At that time, in the early 1960s, it was held by many scientists that only humans had minds and were capable of rational thought. Fortunately, I hadn't been to university and did not know these things," recalled Goodall.

In fact, that was exactly one of the reasons Goodall was chosen by Louis Leakey, one of the world's leading anthropologists at the time, to study chimpanzees in the wild. Leakey, who wanted someone with a mind unbiased by existing theories, also found in Goodall a passion for knowledge, a love for animals and monumental patience — the things that are still with her today.

Back in 1960, Goodall's discovery was met with a telegram from Leakey: "Now we must redefine man, redefine tool, or accept chimpanzees as humans!"

While Leakey's goal was to gain a deeper understanding of his Stone-Age ancestors, for Goodall, her involvement with the animals, especially a female chimpanzee she named Flo and her children, "were very important to my own development", to quote Goodall.

"She was all things that a chimp mother should be — affectionate, playful and supportive. That's what my mother was — she supported me," said Goodall, who was accompanied for the Gombe research by her mother Margaret Myfanwe Joseph (1906-2000), who wrote under the name Vanne Morris-Goodall and passed her writer's genes to her daughter.

Goodall herself became a mother on March 4, 1967, having married three years earlier. Her husband Hugo van Lawick, a Dutch wildlife photographer, was sent in 1962 by National Geographic to film Goodall in Gombe.

According to Goodall, only after becoming a mother herself did she understand why "a chimpanzee mother furiously waved her arms and barked out threats to anyone who approached her infant too closely".

Yet that "anyone" didn't include Goodall. By the time Flo gave birth to her son Flint in 1964, around the time of Goodall's marriage, she had long been an unofficial member of the chimpanzee community. Under Lawick's camera, Goodall played with Flint the toddler, trying to attract his attention with a stuffed toy chimpanzee. In fact, it was a toy chimpanzee given to Goodall by her father that first triggered her interest toward the animals. That childhood interest, kept alive by Goodall, led the young woman to accept a schoolmate's invitation to the latter's family farm in Kenya, where Goodall met Leakey and proved her worth to the anthropologist.

In the 1960s, Goodall's observation, which challenged human uniqueness, was met with "a violent uproar" to use her words. Some sought to discredit her on the ground of Goodall being a young woman. "Comely Miss Spends Her Times Eyeing Apes" was the headline carried by one newspaper.

But Goodall's fame continued to grow. "I was the Geographic cover girl and people said my fame was due to my legs. … By this time I needed to raise money myself, so I made use of it," said Goodall in the 2017 documentary Jane, which shows her roaming the Gombe reserve in the 1960s wearing her now-iconic Khaki shirts and shorts. The man behind the video camera was Lawick, whose 100 hours of previously unseen Goodall footage was only discovered in National Geographic's archives in 2014, twelve years after his passing in 2002.

In 1977, Goodall established the Jane Goodall Institute to support the Gombe research and spearhead multiple community-centered conservation and development programs in Africa and elsewhere. Among these programs is Roots and Shoots, which allows young people to take the initiative in environmental protection.

Acutely aware of the social constraints faced by women, Goodall's research center at Gombe today hosts many woman scientists, who were nearly absent from the field when Goodall began. Goodall also launched projects under JGI to support young African girls by offering them access to reproductive health education and through scholarships to finance their college education.

Goodall herself, unable to initially go to college due to financial constraints, gained her PhD at University of Cambridge in 1966, the eighth person to be allowed to study for a PhD at Cambridge without first having obtained a bachelor's degree.

Horrified by the natural degradation she saw all around her, Goodall has devoted herself to advocacy since the mid-1980s. Having celebrated her 90th birthday this April, she continues to travel approximately 300 days a year over the past few years.

Back in the 1970s, Goodall experienced "a very dark time" as she witnessed the prolonged brutal conflict between two rivaling groups of chimpanzees who used to belong to one big chimpanzee community that included Flo and her children.

"I'd come to accept that the dark and evil side of human nature was deeply embedded in our genes, inherited from our ancient primate ancestors," lamented Goodall.

The "Four Year War", as Goodall calls it, erupted two years after the death of Flo, a dominant female member of her community and the beloved mother of Flint, who was captured on camera as trying to get onto his mother's back as an adult male, when Flo was already "too old to push him (Flint) to independence".

"From time to time, he (Flint) approached her (dead body), as if begging her to groom him, to comfort him as she had always done throughout his life," said Goodall. "Three weeks after Flo died, Flint died too."

At the chimpanzee rehabilitation center founded by Goodall in Pointe-Noire, Republic of Congo, chimpanzees orphaned by the bushmeat trade are nurtured with love and care before being released. In a video on JGI's website, a female chimpanzee named Wounda, who was rescued as a baby and grew up at the center, enveloped Goodall in a gentle hug before heading into the wild.

"The warmth of her embrace is something I shall never forget," said Goodall.