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.
Last but not the least onto my list of biggest dog breeds in the world is none other than a Tibetian Mastiff. They grow to a height of 24 to 26 inches, weighing about 85 to 140 pounds. They usually have a life span of about 10 to 14 years. Tibetan Mastiffs are highly intelligent and independent thinkers.