(Photo : Norman Nan Shi and Nanfang Yu)
The Saharan silver ant is among the most heat-tolerant animals on the planet. Scientists have long wondered how these small creatures can withstand the extreme temperatures in which they live. But it turns out, it all comes down to hair.
The ants choose the hottest part of the day to venture out of their nests in search for food. With surface temperatures topping 158 degrees, few predators are afoot, and the ants can scavenge the corpses of animals who succumb to the intensive heat. The ants must work quickly. Their small bodies, which measure a wee three-eighths of an inch, can only withstand the heat for about 10 to 20 minutes a day. But even utilizing such brief forays, their ability to survive the punishing heat was a mystery. Until now.
New research published in the journal Science reveals the ants sport fine hairs on their bodies, which keep them cool via some amazing feats of evolutionary ingenuity. The hairs are triangular in shape and highly reflective, especially in the portion of the electromagnetic spectrum where solar radiation culminates. The hairs grow parallel to the ant's skin, enabling them to dissipate heat through thermal radiation. This elaborate cooling mechanism enables the ants enough protection to withstand the intense heat in which they hunt.
"That hottest moment of the day is when they can find the largest quantity of dead insects," says Dr. Nanfang Yu, a physicist at Columbia University who participated in the study. "Just a bit later, and those insects may be blown away by the wind or buried by the sand."
For the scientists, the ants are a perfect example of nature's ability to solve complex issues of survival.
"This is a telling example of how evolution has triggered the adaptation of physical attributes to accomplish a physiological task and ensure survival, in this case to prevent Sahara silver ants from getting overheated" Yu says.
The team will now move on to other heat-tolerant species, hoping the information they glean can be applied to industry.
"Understanding and harnessing natural design concepts deepens our knowledge of complex biological systems and inspires ideas for creating novel technologies."