Facts
The adult human brain weighs about 3 pounds (1,300-1,400 g).
The adult human brain is about 2% of the total body weight.

The elephant brain weighs about 6,000 g.

The cat brain weighs about 30 g.

The average human brain is 140 mm wide.

The average human brain is 167 mm long.

The average human brain is 93 mm high.

The human brain has about 100,000,000,000 (100 billion) neurons.

The octopus brain has about 300 million neurons.

The total surface area of the cerebral cortex is about 2500 sq. cm
(~2.5 ft2)

The world record for time without sleep is 264 hours (11 days) by
Randy Gardner in 1965.