Will success spoil Grumpy Cat? The line to snap a photo with him at South by Southwest last winter was around the block, longer than the one for Jim Carrey.

But even when celebrity cats have private trailers, a book coming out and thousands of Twitter followers, their lives don't change all that much. Keep 'em in kibble and catnip, give them adequate alone time and they're happy, say their affiliated humans.

We spoke with the bipeds who oversee Grumpy and Henri, le Chat Noir, to find out a little more about where they came from and how they got here.

Grumpy Cat

She is owned by an Arizona woman named Tabatha "Tabby" Bundesen, but managed by Ben Lashes, a former Seattle rock musician who now lives in Los Angeles and helps people make money off their memes. Other clients include the creator of Keyboard Cat, a family friend, and Nyan Cat.

Grumpy (actual name: Tardar Sauce) shot to fame when pictures of her distinctive scowl — not actually reflective of her mood, Lashes insists — got posted online and shortly landed on the front page of Reddit, the Internet's Holy Grail.

"Everyone was arguing over whether her face was Photoshopped or real," said Lashes, who added that while Grumpy is making at least one appearance a month, she's not overtaxed: "She's a very chill cat."

Henri, le Chat Noir

The angst-filled philosopher star of perhaps the Internet's most sophisticated and artistically shot cat videos, Henri is not quite nine years old. He was adopted from a Seattle animal shelter by professional videographer Will Braden and his family. Braden has been able to quit all other projects for the time being, as Henri — who, like Grumpy, has a book coming out — has become the family's No. 1 breadwinner.

"Henri's always been pampered," Braden said. "Special food, filtered water. Being a pet in the United States is like winning the animal lottery."

One thing Henri doesn't do: travel. "He would freak out," Braden said. "He's a homebody. Plus it would ruin the conceit of his character."

There are plenty of dog videos online, so why do cats seem to rule the Internet? Braden's theory is dog owners have more social outlets.

"Dog owners can take their dogs for walks, go to dog parks," he said. "You'd be looked at like a nut case if you took your cat around on a leash. The Internet is by default a virtual cat park."

Also, he points out, there are at least 8 million more cats in the United States than dogs, and they outnumber pooches in most shelters by at least 2-1. Crazy about cat videos? Adopt one and make your own.