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.
Considered the largest of all dog breeds, the English Mastiff's name seems to fit its best descriptions: massive. This giant dog breed is all brawn and power on the outside, but deep down it is a lovable, mushy companion--and often a bit of a couch potato! These dogs can top the scales at 220 pounds and be 30 or more inches tall. However, it looks like a large percentage of the weight is in their huge heads.