brain weight

The average adult human brain weighs between 1,200 and 1,400 grams (2.6 to 3.1 pounds), making up about 2% of total body mass. While male brains tend to be slightly heavier than female brains, this difference does not correlate with intelligence. The human brain is proportionally larger than that of most mammals, utilizing approximately 20% of the body's oxygen and blood flow.1

Brain size has increased throughout human evolution, with early hominins having brains comparable to chimpanzees. The heaviest recorded human brain belonged to an epileptic patient, weighing 2,850 grams (6.28 pounds). In contrast, the sperm whale possesses the largest brain among mammals, weighing about 7,800 grams (17.2 pounds). Despite their large brains, the intelligence of cetaceans like dolphins and whales is difficult to assess, as their brain mass may be used for processing acoustic information.213