158 degrees Fahrenheit. That’s how hot it can get at midday in the Saharan desert. One tiny insect forages in this hellish environment – the Saharan silver ant.
How does the ant manage to keep its body temperature below their critical maximum of 128.48 degrees Fahrenheit? New research says the secret lies in the ant’s hair.
The ants use a combination of optical reflection and radiative heat dissipation to keep cool in the scorching heat.
“This silvery ant is the champion of the desert, the species that does the best job of surviving in these difficult conditions,” said co-author Gary Bernard. “We thought the silver hairs help control heat and wanted to understand in detail how they worked.”
The team, led by Nanfang Yu from Columbia Engineering, discovered the silver ants have a unique coat of hair on the top and sides of their bodies. This coat of hair is highly reflective under visible and near-infrared light. Think how a car sun shade keeps the inside of your car cooler on a hot, summer day.
This isn’t the only way the silver ant keeps cooler. Researchers also found the hairs were highly emissive in the mid-infrared portion of the electromagnetic spectrum. This effect helps the ant get rid of excess heat through thermal radiation.
Yu compares the effect to how you feel when you first wake up in the morning. “To appreciate the effect of thermal radiation, think of the chilly feeling when you get out of bed in the morning,” says Yu. “Half of the energy loss at that moment is due to thermal radiation since your skin temperature is temporarily much higher than that of the surrounding environment.”
How useful is the coat of hair? Researchers say the coat layer can reduce the body temperature by 5-10 degrees compared to ants who don’t have the coat. The thermal image below highlights how vital the coat is.
Saharan silver ants’ hardiness to extreme heat could lead to human applications. Imagine coating the roof of a building with a substance that mimics the silver ants’ hair coat. 5-10 degrees might not sound like much on a summer day, but it could have major impacts on the amount of power needed to cool a building. I know my house could use it. Anyone who lives in the South knows how much their air conditioners struggle from June-September.
What’s next for Yu and his team? They plan to widen their research to other animals living in extreme environments and learn the strategies they use to adapt to harsh conditions. Who better to learn it from than Mother Nature?
Featured image: Close-up of Saharan silver ant’s head. Credit: Norman Nan Shi and Nanfang Yu, Columbia Engineering