By Varun Bisht
Man with his architectural prowess kneels before the beauty that Mother Nature so effortlessly creates. This world hides, behinds its vibrant colours and serene wonders treasure trove of
scientific knowledge, that changes the way we see our very surroundings, quite literally! Different animals see the world in different colours, but none so interestingly as the Pit Viper.
From deserts to tropical rainforests, members of the viperdae (or viper, for short ) family of snakes have managed to find a home on almost every continent of this planet. The Bushmasters of the Amazon, the Copperheads of North America, the Indian Hypnale and many other subspecies form this venomous family of Vipers. Their vibrant scales make them some of the most beautiful snakes in the world, while simultaneously posing as a warning regarding their deadly hemotoxins ( primarily used to destroy Red Blood Cells, as the name suggests ). But what makes these charming reptiles so unique is the way they see the world around them.
Pit Vipers, being primarily nocturnal hunters, have a very weak sense of vision, leading to a distinct evolutionary trait: the Pit Organ. Found between their eyes and nostrils, the pit gland is a type of thermoreceptor, that picks up Infrared radiation, allowing vipers to see for upto a meter ahead, and hunt their prey on the darkest of nights.
Infrared Radiation (IR) is a type of electromagnetic radiation ( similar to light ) that has a range of 300 GHz to 430 THz, lying just below our range of sight ( visible light’s frequency lies from 430 THz(Yellow) to 730 THz(Red) ) While it cannot be seen, it can be felt as heat. Certain cameras are used to capture these heat signatures, and assign specific colours to different frequencies of IR, creating an image, purely based on how hot a body is. With everything above 5 Kelvin, or -268.15 Celcius emitting Infraded Radiation, nothing down to the smallest detail, or the slightest movement goes undetected. This process is called infrared imaging, and is the principle behind the functioning of the viper’s pit organ, allowing them to easily catch their warm blooded prey ( such as rodents ) with ease.
But this ability has its limitations. Being organs and not cameras, their Pit organs have a range of one meter, beyond which the viper’s senses are blinded. Therefore, in order to catch it’s prey, it must lie still, and wait for it to pass by. A Pit Viper’s Pit organ does not use photoreceptors, but instead has many heat sensitive protein ‘ion channels’. The infrared radiation warms the pit organ, which in turn warms a particular ion channel, that triggers a nerve impulse, ( after which the pit membrane cools down rapidly in order to repeat this process ) allowing the snake to, in a way, ‘see’ heat.
But Infrared Radiation serves a greater purpose than simply feeding snakes. Other uses of infrared imaging include night vision goggles, studying wind and ocean currents, astronomy ( studying the structure of stars and on the basis of the heat generated ), remote controls and even identifying chemical compounds. The applications of IR limited by nothing else but our own imagination. As we go on exploring the wonders of infrared radiation, a pit viper sits in its tree, steady, still, patiently stalking it’s next meal, using the boon of IR bestowed upon it by nature itself.