Dublin Zoo has announced the death of its "much-loved" female Northwest Borean orangutan.
It said Leonie was "an iconic presence since her arrival from Rotterdam Zoo in 1984".
The 44-year-old "was at the heart of our orangutan family for four decades," the zoo added.
Team leader Ciarán McMahon, who first met Leonie in 1995 as a young zookeeper, described her as "the quiet and quirky matriarch of Dublin Zoo".
She "was a character" who was "calm, confident, and adored by visitors and keepers alike," he said.
"Her level of comprehension was astonishing. She would calmly observe the team and often mimic our behaviour. Orangutans are known for this, but Leonie's abilities were exceptional.
"While she was loving towards all our keepers, she was known for having a soft spot for the male staff.
"Then there was her famous fringe. Every morning, she would sit and groom it with the utmost care before she went about her day - a little ritual that made everyone love her even more.
"One moment that stays with me is how she instinctively stepped in to care for a young Mujur, when she needed a surrogate mother. Their bond remained incredibly strong ever since," Mr McMahon added.
He said that, in recent months, Leonie's health declined due to age-related issues affecting her heart and breathing.
"Despite expert care, including consultation with human cardiac specialists, her condition worsened. With heavy hearts, we made the decision to let her go peacefully."
Her death follows the loss of her mate Sibu last year.
"They had been inseparable companions for over 40 years," Mr McMahon said.
Watch: Zookeeper Anthony McClure remembers 'iconic' orangutan
"She was an absolutely fantastic animal to work with," a Dublin Zoo orangutan keeper said.
Anthony McClure, a third generation orangutan keeper at the zoo, had worked with Leonie and Sibu for the last 16 years while his grandfather Gerry Creighton travelled with the two orangutans from Rotterdam to Dublin some 40 years ago.
Mr McClure described Leonie as "iconic", adding that her death is "a huge loss" that has "been quite personal".
He said: "I remember Leonie when I was a boy running through here with Sibu. My grandfather was here for 52 years, Orangutan keeper as well, and my two uncles.
"Even last year with the loss of Sibu. It's almost like my two family members have passed away."
Mr McClure said it was "a privilege and an honour to be able to see the end of their story and their life here".
"It's almost poetic in a way, my grandfather was here when he brought them here as young orangutans, I was here when they passed away," he added.
Leonie's son Carl is currently in Barcelona Zoo and has since had infants of his own, he said.
Meanwhile Mr McClure said the zoo’s last surviving Orangutan, 20-year-old Mujur, will soon be joined by Hutan, a ten-year-old male, as part of a Borneo Orangutan breeding programme, coordinated by the European Association of Zoos and Aquaria.
Until then, he said Mujur will be receiving "a lot of extra attention" from staff.
"We’re going to put a lot of time and effort in with her now," he said.
"So, between ourselves and the new orangutans coming in, she won't be on her own too long," he added.
