Ants thrive in the Sahara desert

There is a class of ants that survive in the Sahara desert despite it being one of the hottest places on Earth, where the surface temperature can reach up to 150 degrees Fahrenheit. These ants, called “silver ants” or Cataglyphis bombycina have recently been found to harbor specialized triangular hairs that enable them significantly increased thermoregulation, as reported in the recent issue of Science. [1] Though the surface of the desert exceeds 150F, the ants can keep an internal temperature of 120F. They do this be frequently cooling off, but the brunt of the work is done by specialized little hairs that are triangular.

Triangular hairs are one of Nature’s way of producing the best solution to a common problem. Hairs can reflect sunlight thus preventing their internal organs from heating up. It turns out that triangular hairs are better than circular hairs because it allows for better total internal reflection. Total internal reflection is a phenomenon where light is entirely reflected and not transmitted if the striking angle is bigger than the “critical” angle. Having a triangular hair helps to reflect much more of the incoming light which prevents heating up the ant!

Preventing solar radiation is a problem that lots of engineers encounter when building devices and infrastructure. This discovery shows that there are more clever solutions to producing high reflectivity thus eliminating a lot of the heat transmission to the inside.

References

1. Shi, Norman Nan, et al. “Keeping cool: Enhanced optical reflection and heat dissipation in silver ants.” Science (New York, NY) (2015).