AP PHOTOS: With California's ugly dog contest coming up, here's a look at past winners

FILE - This Friday, June 21, 2013 file photo shows "Walle" posing for a portrait while competing in the World's Ugliest Dog Contest at the Sonoma-Marin Fair on Friday, June 21, 2013, in Petaluma, Calif. The 4-year-old beagle, boxer and basset hound mix went on to win top honors. The 25th running of the World's Ugliest Dog contest takes place Friday, June 20, 2014, at the Sonoma County Fair in Petaluma, Calif. (AP Photo/Noah Berger) (The Associated Press)

FILE - In this Friday, June 24, 2011, a judge evaluates "Yoda" during the 2011 World's Ugliest Dog Contest in Petaluma, Calif. The 14-year-old Chinese Crested and Chihuahua mix took top honors winning $1000 and a plethora of pet perks at the Sonoma-Marin Fair. The 25th running of the World's Ugliest Dog contest takes place Friday, June 20, 2014, at the Sonoma County Fair in Petaluma, Calif. (AP Photo/Noah Berger) (The Associated Press)

FILE - In this Friday, June 25, 2010 file photo, Kathleen Francis, of Clearlake, Calif., clutches her purebred Chihuahua "Princess Abby" after winning the World's Ugliest Dog Contest, in Petaluma, Calif. The 25th running of the World's Ugliest Dog contest takes place Friday, June 20, 2014, at the Sonoma County Fair in Petaluma, Calif. (AP Photo/Ben Margot) (The Associated Press)

It's that time of year again when dogs with unusually large heads, hairless bodies and other oddities compete to be the World's Ugliest Dog.

The contest at the Sonoma-Marin Fairgrounds in Petaluma, California, which is in its 26th year, is scheduled to start at 6 p.m. on Friday.

Karen Spencer, the fair's marketing director, says the dogs are scored by a three-judge panel in several categories, including special or unusual attributes, personality and natural ugliness.

The winner will get $1,500.

The past five winners have included a duck-footed beagle, boxer and basset hound mix with a waddle, a Chinese crested and Chihuahua mix with a protruding tongue and short tufts of hair and a Chihuahua with a missing eye and a camel's back. Here are photos of the past winners: