March 12, 2016, 7:24 PM UTC / Source: TODAY

By Laura T. Coffey

Sometimes a treat is in order. Pronto. Lickety-split. Like, RIGHT NOW, Mom!

Bretagne (pronounced “Brittany”), the last known surviving search dog who worked at Ground Zero after the Sept. 11, 2001 terrorist attacks, has always been focused, diligent — and incorrigibly food-obsessed. Even today, at age 16 1/2, she regularly saunters up to her longtime handler Denise Corliss like this:

"Bretagne will follow me around with the bag in her mouth until I finally give in and open it," said Denise Corliss of Cypress, Texas.Courtesy of Denise Corliss

“She cracks me up!” said Corliss of Cypress, Texas. “Bretagne will follow me around with the bag in her mouth until I finally give in and open it. She's done this since she was a pup, and ... well, some things never change.”

Corliss told TODAY.com that Bretagne’s polite — and exceedingly optimistic — pantry-raiding moments follow a predictable pattern.

“She brings me a bag of treats, and I set it aside. Then she brings me another bag, and I set it aside. So she brings me a third bag,” Corliss said. “She’s basically saying, ‘We’re gonna play this game all night long until you open a bag for me!’ I took a photo of her doing this because I don’t want to forget this memory. It makes me laugh that here she is, the same old dog all this time.”

Bretagne the 9/11 search dog also is a master of the "pleading eyes" begging technique.Courtesy of Denise Corliss

Many would argue that Bretagne has earned all the treats she wants. She made national news when, at age 15, she returned to Ground Zero with Corliss for the first time since the 2001 terrorist attacks. NBC News' Tom Brokaw interviewed Corliss at the 9/11 Memorial and also spent time with Bretagne, who was a 2014 finalist for the American Humane Association's annual Hero Dog Awards.

9/11 search dog trainer: Memories ‘still vivid’

Sept. 11, 201406:06

Bretagne and Corliss’ first deployment as a trained disaster-search team was to the twisted pile of steel beams, concrete and ash where the World Trade Center once stood. In the years following 9/11, Bretagne and Corliss responded together to numerous other disasters, including Hurricane Katrina, Hurricane Rita and Hurricane Ivan.

Denise Corliss is pictured with her search dog Bretagne at Ground Zero in New York City in September 2001. It was their first deployment together.Courtesy of Denise Corliss

Bretagne retired from formal search work at age 9, but she never lost her love of adventure or her work ethic. Her retirement years have been almost as epic as her younger years, in large part because Corliss realized Bretagne needed just the right physical and mental stimulation as she aged.

At age 13, Bretagne had started to experience so much stiffness and joint pain that she could no longer climb the stairs in her home. Corliss decided to try something: She installed an above-ground pool in her backyard, and she began swimming Bretagne for at least 10 minutes a day.

Bretagne, in forefront, enjoys a swim in February 2016 with Aid’N, another of Denise Corliss' retired search dogs.Courtesy of Denise Corliss

“It makes a huge difference,” Corliss said. “She started doing the stairs again. Then we started focusing on ways to keep her mentally active, and it turns out that helping kids with their reading in school is great for that. It helps her as much as it helps them.”

Bretagne looks on with knowing eyes as Taser, Denise Corliss' current disaster search dog, prepares to climb a ladder during a training exercise in February 2016.Courtesy of Denise Corliss

These days, at age 16 1/2, Bretagne still dons a work vest and volunteers as a reading assistance dog at an elementary school near her Texas home. She also still swims regularly and relishes her daily walks around a pond, where she tries to chase ducks and squirrels.

Her stimulating retirement years made yet more adventure possible for this senior dog: In honor of her birthday in August 2015, BarkPost coordinated an elaborate “Sweet 16” birthday bash for Bretagne in New York City that included an illuminated billboard in Times Square and the dedication of a cobblestone in her honor on the plaza of the 9/11 Memorial.

Late last year, Bretagne also became a star of a non-fiction book about senior dogs and met with former President George H.W. Bush at the George Bush Presidential Library in College Station, Texas.

Former President George H.W. Bush met with Denise Corliss and Bretagne in November 2015. / Courtesy of Denise Corliss

“She just keeps on going and enjoying life,” Corliss said. “She’s such a happy dog. I am so grateful that she’s still here with me.”

Bretagne's life story is chronicled in "My Old Dog: Rescued Pets with Remarkable Second Acts."New World Library

Bretagne's life story is featured in the bestselling book "My Old Dog: Rescued Pets with Remarkable Second Acts," written by Laura T. Coffey and with photographs by Lori Fusaro. Bretagne's chapter includes comments from NBC News' Tom Brokaw and never-before-seen photographs.

Connect with TODAY.com writer Laura T. Coffey on Facebook, Twitter and Google+ and at MyOldDogBook.com.

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9/11 search dog trainer: Memories ‘still vivid’