Under the hot steamy sun of the Sahara Desert, lives one species of ant that will amaze you.
The Cataglyphis bombycina, also known as the Saharan silver ant is the fastest of the world’s
12,000 known ant species, clocking a blistering velocity of 855 millimetres
per second (nearly 1 m/s or 3.6 km/h).
It can travel a length 108 times its own body length per second, a feat topped only by two
other creatures, the Australian tiger beetle, Cicindela eburneola and the California coastal
mite Paratarsotomus macropalpis.
This is nearly the walking pace of a human being, and compared to its body size would
correspond to a speed of about 200 m/s (720 km/h) for a 180 cm (6 ft) tall human runner.
Largely due to the extreme high temperatures of their habitat, but also due to the threat
of predators, the ants are active outside their nest for only about ten minutes per
day.
The twin pressures of predation and temperature restrict their above-ground activity to within
a narrow temperature band between that at which predatory lizards cease activity and
the ants' own upper threshold.
The ants often traverse midday temperatures around 47 degrees Celsius (117 degrees Fahrenheit)
to scavenge corpses of heat-stricken animals.
To cope with such high temperatures, the ants have several unique adaptations.
A few scouts keep watch and alert the colony when ant-eating lizards take shelter in their
burrows.
Then the whole colony, hundreds of ants, leaves to search for food, although they need to
complete their work before the temperature reaches 53 °C (127 °F), a temperature capable
of killing them.
When traveling at full speed, they use only four of their six legs by raising the front
pair of legs.
This way, they don't get in each other's way, and allowing them to travel at a very high
stride frequency.
Keeping track of the position of the sun, the ants are able to navigate, always knowing
the direct route back to their nest, thus can minimize their time spent in the heat.
They produce heat shock proteins (HSPs), but unlike other animals, they do this not in
direct response to heat.
Instead, they do this before leaving the nest, so they do not suffer the initial damage when
their body temperature rises quickly.
These HSPs allow cellular functions to continue even at very high body temperatures.
If they did not produce the proteins in anticipation of the extreme heat, they would die before
the proteins could have their effect.
In the words of one researcher, the production of this protein "does not reflect an acute
response to cellular injury or protein denaturation, but appears to be an adaptive response allowing
the organism to perform work at elevated temperatures during temperature changes too abrupt to give
the animal an opportunity to benefit from de novo HSP synthesis,"
further "the few minutes duration of the foraging frenzy is too short for synthesis of these
protective proteins after exposure to heat."
This and other adaptations led to the ant being called "one of the most heat-resistant
animals known."
Other than that, the silver ants are covered on the top and sides of their bodies with
a coating of uniquely shaped hairs with triangular cross-sections that keep them cool in two
ways.
These hairs are highly reflective under visible and near-infrared light, where the region
of maximal solar radiation when the ants run at a speed of up to 0.7 m/s (2.3 ft/s) and
look like droplets of mercury on the desert surface.
The hairs are also highly emissive in the midinfrared portion of the electromagnetic
spectrum, where they serve as an antireflection layer
that enhances the ants' ability to offload excess heat by thermal radiation, which is
emitted from the hot body of the ants to the air.
This passive cooling effect works under the full sun.