Cats and humans began their grand partnership some 10,000 years ago, when kitties handled humans’ pesky rodent problem and people repaid the felines with food, shelter and companionship.

Now the deal’s off, apparently.

Yesterday a Reddit user shared a video titled “When you get a cat hoping it will help you get rid of the big rat in your yard.”

The video shows the user’s new cat, a tortoiseshell/calico, “solving” the rat problem by befriending the rodent, playing with it and even grooming it.

The video has amassed almost 86,000 upvotes in 24 hours.

The odd friendship between feline and rodent is not without precedent. Studies have shown that cats are not effective rodent hunters in urban settings where rats have gone unchallenged for so long that they rival or exceed the size of most members of Felis catus.

In certain neighborhoods of New York City, for example, researchers observed cats essentially ignoring massive rats and in some cases eating trash side by side with them. The largest rats, apparently aware of the truce, are equally unconcerned by the presence of the cats. Other rats were more cautious around kitties.

The scene reminded me of the time my brother wanted me to bring Bud over to handle his rat problem. At the time he was living on 88th St. in Manhattan, less than a block from Gracie Mansion. His apartment had an unusual perk for Manhattan living — it was a spacious ground floor flat that opened up into a private, fenced-in backyard with grass and a few trees.

In fact, it was one of the first places I took Buddy after adopting him. He was just a kitten, maybe 14 weeks old, and I brought him with me on a warm summer day when my brother had a few friends over for a barbecue.

Buddy made fast friends with my brother’s Chihuahua-terrier mix, Cosmo, and spent the day playing with his doggie cousin, frolicking in the grass and chasing bugs around the yard. Then he got a treat: Steak from the grill, chopped into tiny Buddy-size pieces.

Having a backyard in Manhattan was awesome, but there was a downside. At night the yard was like a stretch of highway for marauding rats who ran across it in numbers with impunity, probably en route to raiding the garbage bins of a bodega on the corner of 88th. The rats were so emboldened and so numerous, you could hear them scurrying across the yard at night.

My brother proposed bringing Buddy over and letting him loose in the yard after dark, letting his claws and predatorial instincts thin the rodential herd.

I declined, using the excuse that Bud could pick up diseases from going to war with the rats. That was true, but I’m sure it wouldn’t have come to that: At the first sign of those rats, Buddy would have run screaming!

(We don’t acknowledge that around him, of course. Officially, Buddy was not set loose upon the Manhattan rats because it would be grossly unfair to unleash such a meowscular, brave and battle-hardened feline warrior upon them.)

It’s one thing if Buddy won’t kill rats. He’s a wimp. But as the Reddit video illustrates, we are apparently closing the chapter on 10,000 glorious years of human-feline partnership, and officially entering the Era of Zero Reciprocity.

We do everything for our cats, and in return they nap, eat and allow us to serve them. From their point of view, it’s a fine deal.