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

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: