Zoos and aquariums across the country participate in #CuteAnimalTweetOff

This is the most adorable Twitter war - ever.

Zoos and aquariums across the country are participating in a #CuteAnimalTweetOff where they share photos on Twitter of cute animals.

It all started with The Smithsonian National Zoo. They shared an adorable photo on Twitter of a seal pup born over the weekend.

Virginia radio show host Sarah Hill replied to the National Zoo's photo and threw it over to the Virginia Aquarium to share a photo of one of their animals.

Challenge accepted. The Virginia Aquarium shared a photo of an otter and osprey.

"We see National Zoo's seal pup, and raise an otter/osprey combo," the tweet read.

And that's when the tweet off began.

The National Zoo came back with a photo of a baby orangutan.

This is Redd, our endangered Bornean orangutan infant. And he is the cutest. Do you fold yet? #challengeaccepted," the zoo tweeted.

The Virginia Aquarium responded, "Don't worry, We're still here" with a photo of a tiny turtle.

From there, #CuteAnimalTweetOff went viral, and Twitter was filled with super cute pictures of animals.

The Bronx Zoo jumped in, challenging zoos and aquariums in California, Arizona, Pennsylvania and Florida. So how about our own zoo? The Houston Zoo couldn't resist.

"The #cuteanimaltweetoff needs to be a regular mid-weekly occurrence!"