When we think of a working dog or cat, we usually imagine a seeing eye dog, or a therapy animal. But every day, a small group of dogs and cats go to work with the most important politicians in England.
Since 1515, when Lord Chancellor Wolsey brought his pet cat to work, there has been a long line of cats dedicated to keeping the government's offices mouse-free.
Today, the "Chief Mouser to the Cabinet Office" is a position of honor, and the current head-cat-in-charge is Larry, who's lived at number 10 Downing Street since 2011.
For a few years, there was no cat at the Prime Minister's residence. After TV cameras caught a rat running across the steps of the building, former Prime Minister David Cameron and his family picked Larry out of a London animal shelter.
There was some concern after Cameron's resignation that Larry would be replaced, or evicted, but it was announced that he would be keeping his job under the new PM Theresa May.
"It's a civil servant's cat and does not belong to the Camerons - he will be staying," a government spokesman told the BBC.
Until recently, Larry didn't share the spotlight with any other pets, but this year other government departments have gotten in on the fun, buying their own office cats.
First there was Palmerston, a black and white cat who is Larry's counterpart at the Foreign Office. Since he was introduced in April, this naughty feline has made a name for himself as the villain of the office cats.
He was caught trying to sneak into Larry's house when the door was left open, and even gave Larry a limpafter a street fight that left poor Larry without his collar. The pair had to be separated by armed guards.
Despite his rude antics, Palmerston is a hit with his 38,000 Twitter followers. Still, he doesn't even come close to Larry, the reigning social media king of the government cats, with 101,000 followers worldwide.
Next, in August the treasury department recruited Gladstone, a short hair who gets along much better with his housemate Larry.
Gladstone is already well-known for his adorable bow ties, and they've earned him more than 8,000 Instagram followers.
As if these three hard workers weren't enough, one more pet has just moved in next door to Larry and Gladstone.
Rex, the Welsh terrier who belongs to Chancellor of the Exchequer Phillip Hammond, only had a modest 600 Instagram followers when his secret account was revealed on Tuesday, but that hasn't stopped people from falling in love with him.
While Larry is kept locked up inside number 11 to keep him from bothering the other pets, he seems to have lots of fun on his own, and might even know how to play cards.
His account has since been made private, but let's hope they open it up again soon. The public deserves to know all the cute shenanigans he gets up too after all!
Hopefully more offices get in on the tradition. We bet having a cute mascot is great for productivity.