1 Certain parts of the brain shrink, especially the prefrontal cortex (an area at the front of the frontal lobe) and the hippocampus. 2  Both areas are important to learning, memory, planning, and other complex mental activities.
Some big, fluffy dog breeds are the chow chow, the samoyed, the standard poodle, the old English sheepdog and the keeshond. The abundant, fluffy coats of these dogs require constant care. Keep Learning.
In fact, for years, two small dog breeds â the Yorkshire Terrier and the Shih Tzu â have landed a place on the American Kennel Clubâs registry of Most Popular dogs in the U.S. The top 10 smallest dog breeds (in alphabetical order) are: 1. Bichon Frise. 2. Boston Terrier. 3. Chihuahua. 4. French Bulldog. 5. Papillon. 6.