On daytime, the surface of Earth is illuminated abundantly by light of spectrum from 250nm-1500nm, that includes near-ultraviolet spectrum (250nm-380nm), visible spectrum (380nm-720nm) and near-infrared spectrum (720nm-1500nm). Our eyes is very sensitive to so called visible light spectrum. It is known that some species of insects and birds are sensitive to ultraviolet light.
But I have not heard of any animal sensitive to near-infrared spectrum (720nm-1500nm). Is there some animal that may see near-infrared? Our world is filled with near-infrared light, for example, most remote control leds emits light of 950nm, CD readers have laser in Near-infrared light, most of plants reflects near-infrared abundantly, night security cameras uses near-infrared lamp too. Near-infrared is widely used in military too.
It seems to be very advantageous for one to be able to see near-infrared. But why we cannot see near-infrared light? Why there seems to be no vertebrates animals with eyes sensitive to near-infrared spectrum? Is there some biological or chemical reason behind that?
Actually we can perceive near-infrared as red light if it is strong enough. But our eyes have very low sensitivity to this spectrum so that it may be reasonable to just say we "cannot see" near-infrared.
p.s.: I am not referring to Far-Infrared light (heat), although sometimes the both are called Infrared light, this name may be misleading.
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