Why is this disturbing at all?  Terriers are supposed to do this... and wild canines (where domestic dogs come from) eat rats as a part of their diet.  What's disturbing is having so many disease carrying rats so close to humans.  I just hope the dog is properly vaccinated.

Disturbing video- PLEASE.If U had even mice where U reside U wouldn't feel the same. These disease carrying flea bags pop everywhere. I think an going to train my chihuahua to do the same.

Personally, I hate to witness the death or injury of ANY living thing, BUT BUT BUT - as others have pointed out, this is a TERRIER doing what terriers do.  I think that unleashing terriers to kill rats is FAR preferable and more humane than using rat poison which makes the rats bleed internally and crawl away to die a lingering death; actually it is preferable to just about any other way I am familiar with, too.
We can't live with rats.  The rats must die.  This is the best way..

Good! Need more of these dogs. Just let them loose in the parks at night and pick them up in the morning. Rats are disgusting disease ridden animals that donot belong in public parks. City also to blame.

Allowing your pet to hurt and kill animals is just one step above being one of those kids who tortures animals for fun that everyone jokes (although it's sometimes true) that they'll become serial killers when they grow up.

And spay/neuter your pets people, come ooonnn.

Actually, the animal/serial killer thing has been debunked. And the "spay/neuter" rallying cry is a crock.

I think if watching your pet maul another animal is entertaining, you probably shouldn't have a a pet in the first place. Disgusting

I wouldn't call it entertaining... I'd call it civil service.  Having so many rats close to human populations is very dangerous.  As long as the dog has it's shots it should be fine... that's what the breed was created to do... wild dogs eat rats for prey.

Rats reared as pets can be loving to their owners, and they are devoted parents to their young. They are intelligent animals. And if given half a chance, they would take over the world. In human civilization, the only limits to their population growth are how much garbage we leave around for them to eat. And the primary way we solve this problem is with poisons that cause them to bleed internally--it's a much more unpleasant death than being shaken to bits by a terrier.

I think most people objecting to this are objecting because it makes them feel 'ooky'. Not because they actually care about the rat. I personally would never encourage my dog to kill an animal. He's certainly got the instincts, but he could just as easily consider a rat to be his friend if we kept one as a pet--he grew up with cats, and seems to differentiate between cats he meets inside (potential friends, though they rarely see it that way) and cats he meets outside (bad! chase! drive away!).

However, if a rabid rat was menacing a kid, I'd sure as hell give his instincts free rein.

By the way, the poisons we use to kill rats also kill a lot of native animals, including our urban Red-tailed Hawks, who eat poisoned rats and squirrels, and die agonizing deaths as a result. A hawk I watched for years in the Bronx died this way. He surely took out a lot of healthy rats before he came across the poisoned one. They surely didn't enjoy being killed by talons any more than teeth.

It's not illegal for dogs to kill rats. It's potentially dangerous to the dog, but not seriously so, if the dog is properly vaccinated, and bite wounds are disinfected. Dogs are tough--so are rats.

I'm fine with trying to extend compassion to all creatures. But it's very hard to know where nature leaves off and civilization begins in a city park. Sometimes you just have to admit that there's more to morality and compassion than whether or not something makes you feel 'ooky.

Awesome!

Baww. Happy dog. Get 'em puppy!!

Doesn't it bother anyone that Washington Square Park is obviously infested with disease-spreading vermin??? Don't children play in that park??? There must be little rat turds everywhere, among other filth!!!

ZOMG there are RATS in NEW YORK CITY!!!!

WHY DIDNT ANYONE TELL ME!!

I expected dog-killing rats after reading the headline. THAT would have been disturbing. This is almost cute.

Awesome! Bloomberg should hire these ratter owners! Can we get a schedule - I can't wait to go spectate! I love dogs, especially terriers, and don't really hate rats, but this process is as ancient and natural as it gets.

I hope the owner knows about all the wonderful diseases his dog is contracting each time it bites into those rats.

Across the Universe playing in the background is a very strange juxtaposition.

I'm in a very small minority as a New Yorker with pet rats, and of course I find this very unsettling. Rats are smart animals, which is why they are so prolific. I know they are a problem, but they don't deserve this.

I think this is a better way for them to die than by poison, animal against animal.  Otherwise, they suffer and stink up buildings etc.  This is nature.  Are you going to say it is terrible for a leopard to kill an antelope and something should be done about that? 

I actually love rats as pets. They are marvelous, wonderful pets.

But as for a terrier killing wild rats, I donʻt have a major issue. Maybe I am nuts.