Just as his star is shining brightest, Uggie the movie dog is hanging up his collar. The sweet-faced Jack Russell Terrier became the four-legged breakout film star of 2011, thanks to his role as the convincingly faithful companion to Jean Dujardin's down-and-out character in The Artist. While he was "snubbed" by the Oscars, the hard-working dog did manage to snag two nominations for next month's inaugural Golden Collar Awards. But Uggie, 10, is starting to slow down, and it's time for him to retire, says his trainer, Omar Von Muller. Here's what critics have to say about Hollywood's loss:

One for the history books: "It's a sad, sad day in the animal kingdom," says Michelle Profis at Entertainment Weekly. Uggie is "arguably one of the most adored pooches of all time." It's heartbreaking to lose such charisma, such "star power."

He made the awards season exciting again: Uggie managed to turn Hollywood's seasonal dog-and-pony shows into a literal one with his red carpet showmanship, says Sarah Anne Hughes at The Washington Post. He is "arguably, one of the best things to come out of this awards season," between his Golden Globe performance and a "fantastic (but failed) campaign to make him an Oscar nominee."

A fleeting favorite: "Nooooooo!" says Jeremy Feist at Pop Bytes. Just when America was falling in love with his talent and charm, he leaves the stage. "Oh Uggie, we didn't know what we had until it was gone." 

Leaving on a high note: The "mean ol' Academy" won't let animals be nominated for an Oscar, says Glen Levy at TIME, but Uggie still had a year few could top. Now that he's retiring, Uggie won't have to worry about trying to out-perform the past 12 months, "which didn't just see him charm audiences worldwide in the current frontrunner for Best Picture but also cropping up in Water for Elephants." 

He's earned his break: This "scene-stealing canine" worked hard to earn his acclaim, and now he deserves a relaxing retirement, says Bryan Enk at The Next Movie. It's too bad his time in the spotlight was so short, but "there's something to be said about getting out once you've hit it big." 

And he's paved the way for others: With "two of the year's most critically acclaimed pooch-oriented performances," says Ben Child at Britain's Guardian, Uggie deserves a break from his grueling 15-hour filming days. But "if animal actors are increasingly becoming as well known as their human counterparts, it should come as no surprise that there is a perky ingenue waiting in the wings" — Uggie's brother, Dash, has been groomed to take his place in the spotlight.