- Mar 5, 2011
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I've seen some anecdotes on the boards about chicken vision at night, colors they can see, etc. I don't think it's been posted here, so thought I would share this recent work on chicken vision. In brief, the authors report that chickens have better color vision than we do, and probably don't have any rods, which means they can't see at night. The kicker: this arrangement arose because chicken dino ancestors were eating us mammals during the daytime, so we had to skulk about at night - yes, there is some evolutionary irony in all of this.
http://www.livescience.com/8099-chickens-color-humans.html
From the article:
http://www.livescience.com/8099-chickens-color-humans.html
From the article:
"Based on this analysis, birds have clearly one-upped us in several ways in terms of color vision," said study author Dr. Joseph C. Corbo of Washington University School of Medicine in St. Louis, Mo. "Color receptor organization in the chicken retina greatly exceeds that seen in most other retinas and certainly that in most mammalian retinas."
Birds likely owe this exceptional color vision to not having spent a period of evolutionary history in the dark, according to Corbo.
Night-vision relies on light-sensitive photoreceptors in the retina called rods, while daytime vision relies on receptors called cones.
During the age of the dinosaurs, most mammals became nocturnal for millions of years. Birds, now widely believed to be descendants of dinosaurs, never spent a similar period as nocturnal animals. As a result, birds have more types of cones than mammals.
"The human retina has cones sensitive to red, blue and green wavelengths," explained Corbo. "Avian retinas also have a cone that can detect violet wavelengths, including some ultraviolet, and a specialized receptor called a double cone that we believe helps them detect motion."
Birds likely owe this exceptional color vision to not having spent a period of evolutionary history in the dark, according to Corbo.
Night-vision relies on light-sensitive photoreceptors in the retina called rods, while daytime vision relies on receptors called cones.
During the age of the dinosaurs, most mammals became nocturnal for millions of years. Birds, now widely believed to be descendants of dinosaurs, never spent a similar period as nocturnal animals. As a result, birds have more types of cones than mammals.
"The human retina has cones sensitive to red, blue and green wavelengths," explained Corbo. "Avian retinas also have a cone that can detect violet wavelengths, including some ultraviolet, and a specialized receptor called a double cone that we believe helps them detect motion."
