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.
The 10 Biggest Dog Breeds. 1  Tibetan Mastiff: This handsome dog is known for the lionlike mane around his head. 2  Caucasian Ovcharka: This breed averages 190 pounds, though itâs not uncommon to see one close to 250 pounds.