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The typical adult human brain weighs about 3 pounds (1.4 kilograms). It contains several billion neurons connected at a hundred trillion synapses. The male brain is bigger; typically 1,300–1,500 cubic centimeters while the female's is typically 1,200–1,350 cubic centimeters. Volume, however, is not necessarily a figure of merit. Neanderthals had very large brains. Whales and dolphins have bigger brains than humans.
Robert Birge (Syracuse University) who studies the storage of data in proteins, estimated in 1996 that the memory capacity of the brain was between one and ten terabytes, with a most likely value of 3 terabytes. Such estimates are generally based on counting neurons and assuming each neuron holds 1 bit. Bear in mind that the brain has better algorithms for compressing certain types of information than computers do.
A excellent site with links to many other sites on brains, is the Comparative Mammalian Brain Collection at
A site cleverly organized to arouse curiosity is:
A comprehensive site on the human brain, with materials specifically for young readers, is:
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Last revised: 20 September 2007.