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Monday, October 21, 2019

faster than Usain Bolt ~ Saharan silver Ants !!

The Sahara desert is located on the African continent covering an area of 9,200,000 square kilometres (3,600,000 sq mi).  The desert comprises much of North Africa, excluding the fertile region on the Mediterranean Sea coast, the Atlas Mountains of the Maghreb, and the Nile Valley in Egypt and Sudan.  This desert is home for so many animals and insects .. ..

Some animals are really fast ..  .. can outmatch humans .. and at first thought, one would be inclined to think of Cheetahs, deers, greyhounds and the like.  There is one yardstick in defining speed – measurement of body length per second – that could throw open newer hitherto unthought of ones.  Cataglyphis bombycina that lives in  Sahara Desert is the unmatched leader.   They track the Sun to always be aware of the shortest route back to the nest. They're covered in unique hairs with a triangular cross-section that keep their bodies cool by reflecting the Sun's radiation, and offloading excess thermal radiation. .. ..  and they move extremely fast, so they can be in and out of the heat as quickly as possible. They spend just a few minutes outside the nest scavenging the carcasses of fallen desert creatures before zooming back in again.

In case you are wondering on what these creatures are – they are ‘Saharan Silver ants’ – to  find out not just exactly how fast, but how the ants get to such speeds, biologists from the University of Ulm in Germany decided to film them in high speed.  First, they had to locate a nest - no easy task, since the ants spend such little time outside. But then, when that was accomplished, the next part was much simpler. They attached an aluminium channel to the entrance, with a feeder at the end to lure them out of the nest. "After the ants have found the food - they love mealworms - they shuttle back and forth in the channel and we mounted our camera to film them from the top," said biologist Sarah Pfeffer. In addition, the team carefully excavated a nest and brought it back to Germany, to see how the ants moved in cooler temperatures.

The sand dunes of the northern Sahara are home to the fastest ants in the world, according to researchers who clocked the insects foraging for food in the blistering midday sun. Video footage revealed the ants galloping across the scorching sand at speeds approaching one metre per second, the equivalent of a house cat tearing about at 120mph. The faster the ants ran, the more they took to the air, in gallops that brought all six legs off the ground at once. At full pelt, the insects travelled 108 times their body length per second, the researchers found.

So with this speed gun – the clear winner is the Saharan silver ant (Cataglyphis bombycina), and the speed is 855 millimetres (33.66 inches) per second.  If it had taken a while to appreciate, that's 108 times the insect's body length per second. Even the cheetah can only manage 16 body lengths per second. Usain Bolt's top speed is 6.2; if he could travel at Saharan silver ant speeds, his top running speed would be around 800 kilometres per hour.  

These tiny ants are amazing. In the Sahara desert, where most creatures avoid going out in the middle of the day to avoid blistering temperatures over 50 degrees Celsius, the Saharan silver ant has evolved a number of adaptations to do just that. They have longer legs than other ants, to keep their bodies farther from the scorching sand. Their bodies produce heat shock proteins not in response to heat, but before even leaving the nest, for maximum heat resistance. To survive, the ants have silvery hairs that reflect the sun’s rays. But even with this coating and other adaptations, the ants can barely survive the 60C (140F) heat and need impressive speed and navigational skills to find food and return to the nest before falling victim to the heat themselves.

Also known as the European fire ant, the common red ant is also found in North America. It can be aggressive and will bite intruders if threatened. The study may also offer potential technical applications for humans, Pfeffer says, such as for walking robots or vehicles that have to deal with staying upright on loose and rapidly shifting sand.  In the Sahara, Pfeffer and her team first located several of the ants’ subterranean nests, then set up small, aluminum channels—with floors lightly covered with sand—on the front steps of the nests. The channels funneled the foraging ants into a more manageable space, so the researchers could film them with high-speed cameras from above as they raced by.  By analyzing the high-speed video, the scientists could calculate the ants’ blistering pace. When the team compared these numbers with speeds of a closely related, slightly larger desert ant, Cataglyphis fortis, the silver ants were twice as fast—despite having proportionally shorter limbs.

The ants also had remarkable coordination on the sand, seamlessly churning between the two sets of three legs that work in unison when running. At higher speeds, the ants would even gallop, leaving all of their feet simultaneously off the ground at certain points. The fast strides and limited contact with the sand may also prevent them from sliding or sinking into dunes as they look for food, the study says.

Interesting !

With regards – S. Sampathkumar
21st Oct 2019.

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