While humans are left with options like a floppy hat or sunscreen to thwart the sun’s desire to super-heat us or give us skin cancer, a species of ants found in the Sahara desert has gone about it in an evolutionary fashion by deflecting the sun’s rays with silvery hairs that act like reflecting mirrors in order to keep the ants cool.
Ants are beating the world’s hottest desert
The Sahara regularly reaches temperatures of nearly 125 degrees Fahrenheit (51 degrees Celsius), but the Saharan silver ants have found a way to walk the desert floor unbothered owing to silvery hairs that deflect the Sun’s heat and its rays.
“The ability to reflect solar radiation by means of total internal reflection is a novel adaptive mechanism in desert animals, which gives an efficient thermal protection against the intense solar radiation,” study co-author Serge Aron, an evolutionary biologist at the University Libre de Bruxelles in Belgium, said in a statement released with his paper published in the journal PLOS ONE “To the best of our knowledge, this is also the first time that total internal reflection is shown to determine the color of an organism.”
The Sahara desert which stretches to cover ten countries with its millions of square miles, is a land dominated by small creatures like snakes and scorpions as well as insects and the occasional rodent. Smaller creatures are able to find shelter in the blistering heat of the day and then go about their business at night. This, however, is not the case with the Saharan silver ants who just don’t seem to mind as they just don’t get hot.
Scientists were well aware of the ants’ ability to manage the heat, but until this study, they hadn’t quite figured out the why.
This is “the first time that total internal reflection is shown to determine the color of an organism,” said Aron. Yes, that silvery color that has been mentioned.
Scientists take to the scanning electron microscope
Aron and his team took a scalpel and shaved a number of the silver ants. Using a scanning electron microscope, the team then took a look at how the hairs dealt with the incoming light. They also studied how light affected the scalpel-shorn ants. The ants with the silver hair had 10 times the reflective power and were able to stay 35 degrees Fahrenheit cooler than their shaved compatriots under simulated sunlight.
Total internal reflection is achieved by the ants because of a corrugated surface and a triangular cross-section that essentially acts as a prism. Light is allowed in but then is reflected back from whence it came when it came into contact with the bottom plate.
Aron, lead author Quentin Willot and others wrote, “Workers come out from the nest during the hottest midday period, when temperatures exceed 50°C (122 degrees Fahrenheit), to scavenge corpses of heat-stricken animals.”
“By restricting foraging activity to the hottest period of the day,” the researchers continued, “the ants minimize the chances of encountering their most frequent predator — a lizard that ceases all activities when the temperature becomes unbearable.”
In addition to the silvery sun-reflecting hairs, the Saharan silver ant also has long legs which keep its body away from the scorching sand and those same long legs make it walk/run faster and keep the ants cooler through convection.
