LOS ANGELES — Animals can melt the human heart, tickle the funny bone or bring us to tears. And thanks to Instagram, YouTube and other online options, you can enjoy their antics simply by following, liking or pinning them.
Dr. Bonnie Beaver, executive director of the American College of Veterinary Behaviorists and a professor at Texas A&M University's College of Veterinary Medicine, says two things make animal photos and videos so popular.
• Many animals have physical traits that subconsciously cause humans to nurture, like large, round heads and large eyes. Think E.T.
• Many images show animals doing something unexpectedly clever, human-like or just plain cute — kittens trying to run up a slide, for example, she said.
"Some do both," Beaver said, "like Garfield and Mickey Mouse."
The Associated Press got hooked on six animals in 2015, from dogs and cats to a panda and a rat, whose popularity is likely to continue into the new year. Here's a look.
Nobody's busier than Grumpy Cat. She had 8.3 million Facebook followers as of Christmas Eve. Her YouTube videos have drawn viewers by the tens of millions.
On Dec. 8, the feline with the comical frown became the first cat immortalized in wax at the Madame Tussauds museum in San Francisco.
The 3-year-old, 4-pounder with feline dwarfism is making her second movie as well as a cartoon series, and is featured in a series of Random House Little Golden Books (the first being The Little Grumpy Cat that Wouldn't). She's also continuing as spokescat for Friskies cat food. Her stuffed animal line will grow in 2016, and there are calendars, socks, tanks, T-shirts, sweatshirts, gift tags, key chains and other souvenirs, said owner Tabitha "Tabby" Bundesen.
Online: youtube.com/user/SevereAvoidance and facebook.com/TheOfficialGrumpyCat.
Nala is a 5-year-old shelter cat, a Siamese and tabby mix who stands out as the most popular cat on Instagram with 2.6 million followers. She also has 1.8 million Facebook followers.
Varisiri Methachittiphan found her in 2010 as an orphaned kitten in an animal shelter in Castaic, Calif., and knew she was the one. Methachittiphan started posting photos of the feline with striped fur and big blue eyes and Nala's popularity exploded. She looks particularly fetching in hats.
Online: instagram.com/nala_cat and youtube.com/user/iamnalacat.
This bundle of fun and fur, a 7-year-old Shiba Inu, has been top dog on Instagram for several years. He lives in Tokyo with owner Shinjiro Ono, who says he was more surprised than anyone that Maru's popularity took off.
"His round face, I think, that's the charm point," said Ono, who compared the dog's look to Japanese cartoon characters like Doraemon or Pikachu. "The round face makes people smile."
Shiba Inus, with their pointy ears and noses, are a popular breed in Japan. But Maru's popularity is worldwide, with 2.2 million followers on Instagram.
Toast is a King Charles spaniel and puppy-mill rescue with a floppy pink tongue that hangs out of her mouth. She's also a celebrity, appearing in fashion shows and shoots, photographed wearing sunglasses and other accessories, and retweeted by the likes of Reese Witherspoon. She's probably best-known for her Instagram feed, toastmeetsworld.
On Jan. 13, Toast will marry a dog named Finn at a hotel in Manhattan. Donations to their wedding registry at www.zola.com/registry/toastandfinn will raise money to fight puppy mills and pay for care for needy animals.
Bei Bei the giant panda baby
Bei Bei (BAY BAY) weighed just 4 ounces when he was born Aug. 22 at the National Zoo in Washington D.C. He was pink, hairless, blind and dependent on his mother Mei Xiang (may SHONG). Four months later, he weighs around 18 pounds and is a lively bundle of fur, muscles, claws and teeth.
Bei Bei's public debut is scheduled for mid January, but fans can follow his every squirm and squeal online. There's a panda cam, Twitter feed, YouTube clips of everything from his first steps to his veterinary check-ups and more.
A video of a rat dragging an entire slice of pizza down the steps of a Manhattan subway station was posted on YouTube on Sept. 22. By the next morning it had been viewed more than 1.4 million times. By late December, the views exceeded 8.7 million. The video flourished on late night TV and earned "Pizza Rat" a nomination in the New York Times' "New Yorker of the Year" contest "for embodying our collective id." Or, as Gothamist.com put it, "We are all this rat."