Nervous System
See also: Bird vision and Avian palliumBirds have acute eyesight - raptors have vision eight times sharper than humans - thanks to higher densities of photoreceptors in the retina (up to 1,000,000 per square mm in Buteos, compared to 200,000 for humans), a high number of optic nerves, a second set of eye muscles not found in other animals, and, in some cases, an indented fovea which magnifies the central part of the visual field. Many species, including hummingbirds and albatrosses, have two foveas in each eye. Many birds can detect polarised light.
Birds have a large brain to body mass ratio. This is reflected in the advanced and complex bird intelligence.
Read more about this topic: Bird Topography
Famous quotes containing the words nervous system, nervous and/or system:
“A car can massage organs which no masseur can reach. It is the one remedy for the disorders of the great sympathetic nervous system.”
—Jean Cocteau (1889–1963)
“A car can massage organs which no masseur can reach. It is the one remedy for the disorders of the great sympathetic nervous system.”
—Jean Cocteau (1889–1963)
“UG [universal grammar] may be regarded as a characterization of the genetically determined language faculty. One may think of this faculty as a ‘language acquisition device,’ an innate component of the human mind that yields a particular language through interaction with present experience, a device that converts experience into a system of knowledge attained: knowledge of one or another language.”
—Noam Chomsky (b. 1928)