Pug

• Pugs are small, flat-muzzled dogs.Photos.com/PhotoObjects.net/Getty Images
  
  The pug is an ancient Asian dog breed that dates to at least 400 BC. It is a toy breed that grows to between 14 and 18 pounds. The pug has a large head with a flattened muzzle and has, as part of the breed standard, deep, long wrinkles on the face.
  
  

Shar-Pei

• The Shar-Pei's scowl-like expression was believed to ward of evil.Jupiterimages/Photos.com/Getty Images
  
  The Shar-Pei is a large dog breed, growing to almost 2 feet at the shoulder and weighing up to 60 pounds. It is a hunting and guard dog that originated in China where its distinctive look is thought to ward off evil spirits. The dog has loose skin folds covering its entire body and has a deeply wrinkled face.
  
  

Bulldog

• Bulldogs were once a fierce, tenacious breed.Jupiterimages/Photos.com/Getty Images
  
  The bulldog is a short-legged, sturdy dog that originated in the United Kingdom. Its flat face is an adaptation bred for its former purpose in bull baiting. The sport has long been illegal, and modern-day bulldogs have had the aggressive traits bred out. The jowls and loose skin around the face give it a wrinkled appearance.
  
  

French Bulldog

• French bulldogs have small, heavily jowled faces.Chris Amaral/Digital Vision/Getty Images
  
  The French bulldog was selectively bred by British lacemakers in the 19th century from the bulldog to create a toy class breed. During the Industrial Revolution, the making of lace was moved to France along with it the dog breed. It is smaller and more slender than the bulldog, but has the same jowled face with loose, wrinkled skin.
  
  

Mastiff

• Mastiffs have huge wrinkled faces.Jupiterimages/Photos.com/Getty Images
  
  The mastiff is one of the biggest dog breeds, dating to 3,000 B.C. It is a heavy, powerful animal with a huge head, jowled cheeks and copious loose skin, creating wrinkles. There are several breeds of mastiffs, all of which generally have wrinkled skin in the area of the face.
  
  

Bloodhound

• The bloodhound has been described as a unique-looking dog in a baggy suit.Jupiterimages/Photos.com/Getty Images
  
  The bloodhound dates to Medieval Europe, where it was bred as a hunting and tracking dog. It is still used for its excellent sense of smell and tracking abilities. The breed has copious amounts of loose skin all over its body, especially in the face, giving it a deep wrinkled appearance.