Updated

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: