Jack Hanna has been working with animals for decades as a zookeeper, a zoo director and a popular guest and host on a wide variety of television shows on which he shared his knowledge and passion for wildlife.

Now, it appears that Hanna's animal handling days are over as the star's health continues to decline. He was diagnosed with early Alzheimer's in 2019, and in the past four years his condition has worsened so much that he can't remember huge chunks of his life, or even his family.

According to a profile done by The Columbus Dispatch – Columbus, Ohio, is the location of the zoo where Hanna spent most of his career – he can remember his wife, Suzi, his dog, a golden retriever named Brassy, and occasionally his oldest daughter (he has three).

One of the many things he can't remember is Columbus itself.

JACK HANNA, FORMER COLUMBUS ZOO DIRECTOR EMERITUS AND TV HOST, DIAGNOSED WITH DEMENTIA, FAMILY SAYS

Jack Hanna smiling at event

Jack Hanna has been suffering from cognitive issues for years. (Joe Coomber/FilmMagic)

The article mentions that when the journalist introduced himself and said he was from the Ohio city, Hanna responded, "Have I ever been to Columbus, Ohio?"

As his wife describes, he spends a great deal of his time sitting on the back porch of their Montana home. He struggles with any change to his routine, and he's even reacted in anger toward her if there's a change that upsets him.

She recalled one instance in which he told her that he'd gone blind, and after taking him to see a doctor, it was discovered that what actually happened was that he'd stacked five pairs of contacts in his eyes, forgetting over and over that he'd put them in.

A photo of Jack Hanna with his wife, Suzi.

Jack Hanna poses for a photo with wife Suzi in 2018. (Michael Tullberg/Getty Images)

"My husband is still in there somewhere," she told the newspaper. "There are still those sweet, tender moments – you know, pieces of him that made me and the rest of the world fall in love with him. It’s hard. Real hard some days. But he took care of me all those years, and so it’s my turn to take care of him."

JACK HANNA URGES TOUGH RULES ON EXOTIC ANIMALS

The couple's oldest daughter, Kathaleen, explained why they were speaking out about his condition now, saying, "If this helps even one other family, it’s more than worth sharing dad’s story. He spent a lifetime helping everyone he could. He will never know it or understand it, but he is still doing it now."

Suzi also discussed the daily walks by the nearby river that she and Hanna take together – walks that take up a lot of time as Hanna stops to touch the trees and tell them things like, "Hello tree, you are a pretty tree. I love you tree. God bless."

Jack Hanna appeared on talk shows

Jack Hanna was known for bringing animals on a wide variety of talk shows. (Donna Svennevik/Walt Disney Television via Getty Images)

"I want to hold on to these walks as long as I can," she said. "I remember the day this all officially started. The day the doctor told us what it was. I’ve just tried to hang on to the little pieces of Jack since then."

When he was diagnosed in 2019, he immediately denied having any sort of problem with his cognitive function, which doctors say is normal. He did, however, make his wife promise that she would never tell the public about the news.

"People will think I’m dumb, Sue," Suzi remembered him saying. "We can’t tell anyone, Sue. Promise me."

She did promise, but in 2021 allegations were made that he had lied to the public about the animals he showed in his television appearances, and that instead of being taken from the zoo, they had been bounced around between backyard breeders and smaller zoos that were essentially "animal prisons."

Jack Hanna poses with a snow leopard

Jack Hanna's family says that he struggles to remember his children. (Axelle/Bauer-Griffin/FilmMagic)

In his condition, Hanna wasn't aware of what was going on, in part because his family did their best to keep the news away from him.

"It was hell – absolute hell," Kathaleen recalled of the controversy. "He would never knowingly allow animals to suffer. They created a narrative around my dad that isn’t true, and he couldn’t defend himself. My dad would have faced all this head-on like he always did… He dedicated most of his life to protecting animals. It was all so heartbreaking."

He did eventually see his face on TV while the controversy was in the news, and he assumed that meant his family had announced his diagnosis.

"He just kept saying, ‘Sue, you told them, didn’t you? You promised me, Sue, you promised,’" Suzi said. "It would have broken Jack’s heart to hear what was going on at the zoo. If we had tried to tell him, he wouldn’t have understood."

Jack Hanna poses for a portrait in 1992.

Jack Hanna has also hosted his own shows. (Steve Fenn/Disney General Entertainment Content)

As the news continued to make waves, more and more people wanted to hear from Hanna himself, and that's when his family decided they had no choice but to tell the world about his Alzheimer's.

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"It killed me to break that promise," his wife said.

Later in the profile, Hanna's middle daughter, Suzanne, said her father simply doesn't know who she is anymore.

"He just stopped remembering who I was in all ways," she said during a tearful conversation with her mother and sisters. "Whether it was in person or by phone, he had no idea I was his daughter. I think it’s because he didn’t see me as much because I got married so young and I moved away."

Jack Hanna poses with his wife, daughter and a snow leopard

Jack Hanna poses with his youngest daughter Julie and his wife. (Tim Boyles/Getty Images)

Suzi remains his main caretaker, with help from their children when they can make it to Montana. The daughters have begged their mother to get professional help to aid in his care, but she refuses, saying, "I just want it to be your dad and I for as long as I can."

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"The river, the sun, Brassy, our walks… That's what we have left. The Jack people knew isn't here anymore, but pieces of my husband are. And I'm going to hang onto them for as long as I can."