Days after a shocking feud between the Irwins – previously one of the most wholesome families in the public eye – kicked off on social media, fans are still searching for meaning behind Bindi's claims her grandfather has "ignored" her for years.
Now, a glimpse back in time 13 years ago, when Steve Irwin's conservationist father and hero Bob left the family business, has shed light on the alleged animosity.
According to the Daily Mail, Bob stepped away from Australia Zoo – the wildlife park he established in 1970 – amid concerns it was becoming an overcommercialised "circus".
The circumstances surrounding Bob's sudden departure in 2008 have resurfaced this week after 22-year-old Bindi accused the 82-year-old of "psychological abuse" in a Facebook post on Sunday.
According to various reports cited by the Daily Mail, Bob was worried the Sunshine Coast tourist attraction was losing its focus on the animals, and even feared a then nine-year-old Bindi was being pushed into the spotlight far too young.
Bob turned his back on the zoo two years after the death of his son — around the same time his daughter-in-law Terri was said to be planning a five-year expansion "to make it Australia's peak tourist destination with a Disneyland feel".
Bob's opinion of expansion plans
The move to make the zoo such a spectacle didn't sit well with Bob, who by his own admission, felt he'd become an unwelcome presence as the business grew.
"It's a strange feeling to spend half your lifetime building something up and walking away from it," he told ABC's Australian Story in April 2008.
"I was becoming a disrupting influence, not that I meant to be."
Further clues this may have contributed to Bob allegedly shunning the family in the years that followed were in his farewell statement from the zoo, in which he made no mention of his daughter-in-law.
In it, he said he wanted to "continue Steve's dream" of wildlife conservation at his own reserve in Kingaroy – implying Terri's vision wasn't what his son would have wanted.
Responding, Terri denied rumours a personal rift was behind Bob's decision to leave.
"I just can assure everyone that I love Bob dearly … he's gone through so much grief losing his [first] wife and his only son that I will respectfully just leave it at that," she said at the time.
Financial settlement between family members
In financial documents unearthed by Daily Mail, Bob received a $1 million package when he departed the zoo – which he had founded as Beerwah Reptile Park in 1970.
He was also offered a $100,000-per-year pension as part of an existing deal.
In 1992, Bob and his first wife, Lyn, handed over ownership of the zoo to son Steve and daughter-in-law Terri, with the family agreeing to a retirement package given Steve and Terri were unable to fork out $300,000 at the time.
The arrangement was reportedly made that Steve and Terri would pay Bob and Lyn, who died in 2000, a wage for the rest of their lives in exchange for the former reptile park.
Of course, Steve and Terri went on to have huge success with the zoo once it was in their name, given Steve had developed an internationally-recognised profile as The Crocodile Hunter.
In 2008, when it was eventually put in Terri's name following Steve's death, an Australia Zoo spokesperson said: "Australia Zoo, under instruction from Terri Irwin, will continue to provide financial assistance to Bob with a retirement package worth over $1m, plus an ongoing annual pension of $99,840 per year.
"The $1m package includes the purchase of Mr Irwin's 632-hectare property near Kingaroy, and the construction of a new home, a car each for him and his [second] wife [Judy] plus a bulldozer and other equipment."
Suggestions Bob was worried about Bindi's child stardom
Amid Bob's tense departure from the business, various reports suggested he was also "upset" with Bindi's growing media profile in the years after her father's death.
Terri, however, has always maintained her daughter embarked on a career in the media spotlight willingly because of her natural love of performing.
Bindi slams Bob in shocking Instagram post
In a Father's Day post (Father's Day outside of Australia was June 20), dedicated to her own father, her husband, Chandler Powell, and her father-in-law, Bindi was asked why she left Bob out of the tribute. In a rare display of candour for the squeaky-clean new mum, Bindi didn't hold back with her response.
"Unfortunately my grandfather Bob has shown no interest in spending time with me or my family," she wrote, according to 7 News.
Bindi went on to claim that Bob has even gone so far to return gifts she's sent him over the years — after opening them.
"He has returned gifts I've sent him after he opened them, he has ignored my correspondence and from the time I was a little girl he has ignored me, preferring to spend time doing anything else rather than being with me," Bindi wrote.
"He has never said a single kind word to me personally. It breaks my heart but it is not healthy to engage in an abusive relationship.
"I hope everyone remembers to be kind to one another but most of all care for your own mental health," she added.
"I have struggled with this relationship my entire life and it brings me enormous pain."
According to Bindi, who welcomed her first child in March, her mum Terri continues to write letters and send gifts to Bob — only to be ignored as well.
She also alleged that the family has been supporting Bob financially since 1992 and is still sending him weekly payments. Despite how he has purportedly treated the family for decades, she maintains she still wants to make sure he is taken care of.
"We built him a house on a beautiful property and will always do our best to ensure his wellbeing."
Bob's family responds to explosive claim
Entertainment Reporter Peter Ford told Sunrise that he spoke to Bob's wife Judy shortly after Bindi's post went viral.
According to Ford, the family was unaware of the comments.
"They were pretty shell-shocked by it and when I rang and read to his wife Judy the details, they're not on social media, so they were not aware of what was going on at all, I think they were pretty shocked and devastated," Ford shared.
"That's just the feeling I got. They didn't say that to me and they did not come back and offer any kind of reply or response."
Another member of the family angrily disputed Bindi's claims in a Facebook post of her own, defending Bob or "Poppy" as she affectionately calls him.
Bethanny Wheeler explained that she is the "the granddaughter of Bob Irwin via marriage of my father and my Stepmother Mandy as a very young child", and called Bob "the most genuinely beautiful human on this planet and has NEVER spoken out or put down anybody! He is a man who sits silently and battles his demons alone, in what is great sadness. He doesn't retaliate, only prays for his grandchildren's safety and good lives."
Wheeler wrote that her "sisters and brothers will happily back me up when I say that Bob Irwin is a passive and beautiful human and these lies need to stop".
Bob's biographer weighs in
Bob Irwin's biographer also came to his defence, saying he had been "devastated" by Bindi's claims of abuse.
"To write that there is psychological abuse from the kindest, most beautiful soul I have ever met, is heartbreaking," she wrote, saying Bob has been "devastated to his core."
"Unbeknownst to you, and what you know, he is suffering deeply for the loss of his family … He has done all he knows how to do and that is bury his head in the sand because that's how he copes," she continued.
"He's not someone who is out there about reaching out and communicating, he's like your dad was. An introvert and not someone who can navigate people well.
"He loves your dad, and you guys more than you know. This should be a private matter not written about on Facebook."
Bob and Steve's close relationship
Steve had boundless enthusiasm about his fellow conservationist father, who he dubbed "the legend of the universe".
Steve told the ABC's Enough Rope in 2003: "He was everything I wanted to be. And all I've done in my life is follow in his footsteps, mimic him and try to be him. And nowadays I just try to make him proud."
The father and son had just wrapped up a month-long crocodile research project in Cape York when Steve was killed in his September 2006 freak accident.
"You never expect that's the last time you're ever going to see your son, but I certainly had a feeling he sensed something was about to happen," Bob said after the accident, in which Steve died after being pierced in the chest by a stingray barb while filming on the Great Barrier Reef.
Announcing his book's release in 2016, Bob said that "when the world lost Steve, the animals lost the best friend they ever had, and so did I".