Buttonwood Park Zoo is mourning the loss of 16-year-old cougar Riley

Buttonwood Park Zoo officials and staff have announced "with heavy hearts" the recent loss of longtime zoo resident Riley the cougar.

According to a press release, Riley was 16 years old when he died on Thursday, June 12, "due to age-related complications." It was the second loss for Buttonwood Park Zoo in the past few months, following the May 28 loss of red panda Marie.

"Riley was the second oldest male cougar living in an Association of Zoos and Aquariums (AZA)-accredited facility and a cherished member of the BPZOO family," BPZoo officials wrote in the release. Riley arrived at the New Bedford zoo in 2009, the release reads, after he'd been "orphaned in the wild in South Dakota" and was "deemed non-releasable due to his age."

According to the release, Riley spent most of his life living with a female cougar named Nikki, whose 2024 death was the result of "a period of rapid decline due to end-stage chronic kidney disease."

Riley's life was 'remarkably long'

In the release, BPZoo officials described Riley's 16-year lifespan as "remarkably long" and "a testament to expert care, patience, and the powerful bond between animals and the people who care for them."

“Riley lived much longer than he should have because of the care we were able to provide him,“ said BPZoo veterinarian Dr. Emmy Budas, who, according to the release, was able to "build a relationship with Riley that made it easier for her to monitor his blood pressure."

In 2023, Riley was diagnosed with chronic kidney disease and systemic hypertension, after which Budas "worked closely with animal care staff to build a relationship with Riley that made it easier for her to monitor his blood pressure," the release reads. Budas credits Riley's "demeanor and eagerness to participate in training sessions" as the reason why zoo staff "were able to so closely monitor his health for the last two years of his life."

Read more local news: A $400M project to rebuild I-195/Route 18 begins soon. Here's what to expect.

“Despite Riley being an older cat, he was very willing to learn new behaviors for obtaining blood pressures and performing blood draws from his tail. He was a very smart, motivated, and calm cat, which is what made training these new behaviors at an old age possible," Budas said. "He truly was the best and most tolerant big cat I have ever worked with."

Riley remembered as a fan-favorite, 'bestest boy'

“Guests and staff alike were drawn to his captivating presence, and his absence will be deeply felt across the zoo grounds,” Buttonwood Park Zoo Director Shara Rapoza is quoted in the release. “For the animal care and veterinary team, Riley was more than just a resident — he was family. His passing, especially in a year when we’ve experienced significant loss at BPZOO, has been particularly hard on our dedicated staff.

"We’re grieving, but we’re also reflecting on the incredible care and connection Riley experienced throughout his long life."

Not too long ago: Red panda at New Bedford zoo has died. Marie gave birth to the first red panda born at BPZoo.

"He still had his spots," said Buttonwood Park Zoo care team member Stephanie Durrette-Mederios, despite the tendency for cougars' spots fade with age. Durrette-Mederios cared for Riley for most of his life, according to the release. "He was just the bestest boy."

“He loved his fish — especially diving for them in the pool," said Katie Harding, "another long-term member" of Riley's care team. "He was easy to engage with, and he loved to play with Nikki and with his keepers."

Riley leaves a New Bedford legacy

According to Budas, Riley had been one of the zoo's "last remaining residents" to have arrived shortly after Buttonwood Park Zoo's "transformative reopening in 2000," and, in the time since, has stood as "a symbol of continuity and resilience through decades of growth and change."

"While we mourn the loss of this extraordinary cat, we also celebrate the many years he spent as an ambassador for his species, helping to inspire awe and appreciation for North America’s majestic wild cats," the zoo's release reads. "Riley’s legacy lives on in the hearts of those who knew and cared for him, and in the generations of visitors whose love for wildlife was sparked by his story."

This article originally appeared on Standard-Times: Buttonwood Park Zoo: Cougar Riley's death 'age-related'