We hardly know those eyes
- University of California, Davis, Department of Ophthalmology, 4860 “Y” Street, Suite 2400 , Sacramento CA. 95817, USA; irschwab@ucdavis.edu
The electromagnetic spectrum of the sun produces a peak of energy in the region of the shorter wavelengths of the visible spectrum. It is no surprise, then, that life on earth has capitalised on this energy source for growth and sensory adaptations. But there are other portions of the spectrum that provide useful sensory information for those organisms capable of its recognition.
Rowley’s palm viper (Bothriechis rowleyi) seen on this month’s cover, is an arboreal, montane representative of Crotalinae, an elite subfamily of snakes capable of radiant thermal detection and poisonous prey dispatch. A more primitive but related family, Boidae, that includes the boas, also possesses infrared detection abilities, but these species have no poison.
The nerve endings in the infrared sensitive pits located anterior to the eyes in these pit vipers are capable of detecting temperature differences as subtle as 0.05°C at the surface of the receptor. These magnificent snakes can even strike, based on thermal clues alone, as the pits face forward with overlapping fields, thus making the thermal …
