Cute animals -- especially baby animals -- rule the web. Every time a new one comes up, the details vary, but the fascination is the same.

It's kind of like a game of Mad Libs, where you pick random words to fill blanks in a sentence: In 2024, a (pygmy hippo) from (Thailand) named (Moo Deng), which means (bouncy pork or meatball), captured internet users' hearts, thanks in part to (being slippery looking) and (biting her zookeeper's butt).

Cute animals have been beloved for as long as animals and humans have existed. You might have learned in school about ancient Egyptians treasuring their cats -- though it's false to say they "worshipped" them (instead, they did have deities that they believed shared feline traits). And one 1911 book, Kittens and Cats: A First Reader, shows cats dressed up and captioned in truly memelike ways. In the internet age, Grumpy Cat became a $100 million meme machine in the 2010s, and other pets, including big-eyed Lil Bub and Noodles, the "bones/no bones day" pug, also hit it big. Currently, cats such as The Stinkwalker, Lucille the senior rescue cat and earless Cheddar Bob are finding new generations of fans. 

Why do we love them so? For one thing, medical studies have shown we're actually hardwired to love and protect little vulnerable things. And as anyone who's followed Snoopy in the Peanuts comic strip, shared a cat video, or bought a puppy calendar knows, we relate to our animal friends in a special way. They stand in for us in jokes and memes, and their mere innocence brings smiles.

But currently, there's a trend toward following unusual animals -- hippos and anteaters and penguins and seals, the kinds of critters you'd never have in your own home. Here's a look at just some of the amazing animals that are currently charming millions online.

Moo Deng: Pygmy hippo popularity

Moo Deng, born in July at the Khao Kheow Open Zoo in Chon Buri, Thailand, deserves her viral fame. She's cute and sassy and somewhat weird, because her skin is always wet. Saturday Night Live cast member Bowen Yang played her on Weekend Update on Sept. 29, and kept asking to be sprayed with a hose, which is apparently a favorite game of Moo Deng. She's also known for biting her zookeeper's butt (her teeth are just coming in, so it's not as painful as it sounds).

Moo Deng always looks kind of naughty, so she's a prime candidate for memes, where her tendency to scream becomes a relatable reaction to this world we're living in. 

How to follow Moo Deng: You can tune in and try to catch a glimpse of the little meatball on the zoo's 24/7 webcam. Plus, the Associated Press streamed an hour of Moo Deng cuteness on Sept. 19, and you can watch that on YouTube.

Pesto the penguin: He's HUGE

Just as Moo Deng began to go viral, another baby animal waddled onto the scene. Pesto the king penguin, who lives at the Sea Life Melbourne Aquarium in Australia, is only a baby, but you wouldn't know it from his size. He looks enormous compared with his penguin buddies, weighing in at around 49 pounds and chowing down on 25 fish a day.

The aquarium where he lives tries to explain his bulk on its web page, writing, "Pesto's impressive weight is due to a number of factors. Firstly, his biological dad, Blake, is our biggest and oldest penguin. Secondly, he's had amazing parents raising him! So, the combination of good genes and good parents explains his current weight, but he will lose a lot of this when he fledges (develops his adult feathers.)"

But eating so much comes with natural consequences. CNN notes that Pesto poops every 15 minutes, and the staff hurry after him to keep his enclosure clean.

Pesto is so popular that the aquarium is even selling merchandise with his image on it, plus a plushie. And even singer Katy Perry visited him.

How to follow Pesto: The best ways I've found to keep up with Pesto are the aquarium's TikTok and Instagram feeds.

Biscuits the seal: Sad-faced but lovable

Seals have always been a favorite animal for many, and a certain little sad-faced seal named Biscuits doesn't know why she can't be just as popular as Moo Deng or Pesto.

Biscuits was found separated from her mother near the Royal Vancouver Yacht Club, weighing just 15 pounds, and was admitted to Canada's Vancouver Aquarium Marine Mammal Rescue Center on Aug. 2. The center notes that Biscuits has been moved to a larger rehab pool since admission because she can now eat fish on her own and compete with the other seals for food.

"She will move between pools as she progresses further and develops her skills until she reaches her release weight," the site says. "It can take just a few weeks or several months before a patient is ready for release, depending on health status and treatment plan, weight gain and transport availability."

She might not have Moo Deng or even Pesto's popularity yet, but a motherless seal who sits up like a human? Get Disney on the phone, we've found their next heart-wrenching movie subject.

How to follow Biscuits: The Vancouver rescue center has "patient progress" and "patient updates" for Biscuits on its webpage, though the last update is dated Aug. 27.

Beardsley Zoo anteater: Worm tongue for life

Anteaters have one of the funniest names in the animal kingdom, named after their diet of ants and termites. These mammals belong to the suborder Vermilingua, which translates as "worm tongue," and once you see the tongue in question, you'll understand why. Anteaters have no teeth, but their tongues can grow up to two feet long, and help them suck prey into their mouths.

Connecticut's Beardsley Zoo in Bridgeport welcomed a baby giant anteater in late summer, and while it hasn't achieved the fame of Moo Deng yet, come on, it's an anteater, it's already hilarious with just that enormous pink tongue alone. Add in the fact that it might ride around on its mom's back for a full year, and this little guy is as intriguing as any cat video.

The zoo's fact sheet about the baby doesn't list a name for it, though an article from USC's Annenberg Media is just dubbing it "Beardsley," which isn't a terrible name. 

How to follow the baby anteater: Maybe the Connecticut zookeepers don't want to seek out the fame of Moo Deng and the rest, because they don't seem to have set up a webcam or TikTok account to follow the little one. But the zoo does have Facebook and Instagram, so he might make appearances there.