Nervous System Capacities

In order to begin to relate neuronal computing capacity in various species to current and future non-biological computing capacity it is necessary to understand the number, connectivity, speed and information capacity of neuronal network from a variety of species.

Animal	Brain Mass	Neurons	Power	Capacity	Source
	grams		bits/sec	bits
C. elegans		302	< 10⁵	< 10⁵	White, 1986
Snail		10⁵	10⁸	10⁸	Moravec, 1988
Bee		10⁶	10⁹	10⁹	Moravec, 1988
Hummingbird	0.1	10⁷	10¹⁰	10¹⁰	Moravec, 1988
Mouse	1	10⁸	10¹¹	10¹¹	Moravec, 1988
Human vision	100	10¹⁰	10¹³	10¹³	Moravec, 1988
Chimpanzee	340	0.25×10⁸	0.25×10¹¹	0.25×10¹¹	Reinartz, 1996
Cow	500	0.3×10¹¹	0.3×10¹⁴	0.3×10¹⁴	Klinowska, 1994
Human	1500	6.0×10¹⁰	10¹⁴	10¹⁴	Moravec, 1988
Dolphin	1700	1.1×10¹¹	1.1×10¹⁴	1.1×10¹⁴	Blackstock, 1970
Elephant	3000	2×10¹¹	2×10¹⁴	2×10¹⁴	Moravec, 1988
Sperm whale	5000	5×10¹¹	5×10¹⁴	5×10¹⁴	Moravec, 1988

Some of the neuron number, power and capacity values are interpolations

For this data to be really accurate it should be recomputed based on the neuronal density and scaling of different brain regions. It is also necessary to consider that each neuronal activation potentials may carry more than a single bit of information, perhaps 2-3 bits. Information about these considerations were in Science articles in 1995-1996.

Notes:

Blackstock lists the brain weights of Bottlenose Dolphin (Tursiops truncatus) at 1700 grams, Elephants (Proboscidae) at 6075 grams, Fin Whales (Balaenoptera phipalus) at 7200 grams and Sperm Whales (Physeter catadon) at 9200 grams.
Kinowska lists the brain weights of Bottlenose Dolphin (Tursiops truncatus) at 1600 grams, Elephants (Proboscidae) at 7500 grams, Pilot Whales (Globicephala melas) at 2670 grams Killer Whales (Orcinus orca) at 5620 grams Fin Whales (Balaenoptera phipalus) at 6930 grams and Sperm Whales (Physeter catadon) [male] at 7820 grams.

Physeter macrocephalus

The High North Alliance brochure lists the brain weight of Mice (Mus ?) at 0.4 grams.

I personally have read that although human female brains on average may weigh less than male brains, they are packed more densely which would allow equivalent processing capacity.

Sources:

White, J. G., Southgate, E., Thomson, J. N., and Brenner, S., "The structure of the nervous system of the nematode Caenorhabditis elegans", Phil. Trans. R. Soc. Lond. B 314:1-340 (1986).
Moravec, Hans, Mind Children, 1988, Table 1, pg 168.
Blackstock, Regina, Dolphins and Man.... Equals?, 1970, 1995.
Klinowska, Margaret, Brains, Behavior and Intellegence in Cetaceans, 1994.

Brain size, body weight and intelligence

Reinartz, Ulrich, Tursiops Homepage, 1996.

See Also:

Watson, Paul, "The Paragon of Animals"

Created: circa late 1996
Last Modified: January 3, 2001
Author: Robert Bradbury