Jul 05

Ants

by in Africa, Kenya

E.O. Wilson would love this corner of Africa.  In our first few days in northern Kenya we have seen creatures great and small, including three distinct and fascinating species of ants.

The first was the safari ant.  We had just arrived at Lewa and our guide Simon was coaxing the Land Rover across a shallow stream bed.  When we reached the other side, we saw dark rivulets of mud running parallel to the stream and then draining into it.  Upon closer inspection, we realized that it wasn’t mud at all but millions and millions of tiny black ants.  Simon casually noted that they were migrating and would be moving their colony across the stream.  He then added that this particular species was carnivorous and was given wide berth by all creatures, including humans and the mighty python which will avoid making a kill in proximity to a safari ant colony because the ants will devour the python as it attempts to eat its prey.

The ant, which looked only slightly larger than your average picnic ant, looked innocuous enough to me. How could they possibly best an African python? 

Simon went on to explain that it always moves in massive numbers and that it has slicing mandibles on its head.  Once it locks onto you, it doesn’t let go.  In a medical pinch, this ant has been used as “bush sutures;” a skin wound can be stitched closed by placing a line of ants on it.  Once they grab on, you pinch their heads off and their locked jaws hold the wound closed. 

However, these ants don’t actually kill with those sharp tiny slicers—they kill by suffocation.  They attack their target with overwhelming numbers, entering through every orifice and actually filling the air passages. Once the creature is dead, they slowly devour it.  While large numbers of ants die in the process, the vast majority of the colony feeds and survives.  I was glad we weren’t walking.

The next species we encountered was called a harvester ant.  These ants are also small and black but not nearly as carnivorous.  Their nests are easy to spot because the ants secrete formic acid around the entrance, creating a circular patch in which nothing will grow (we were told that you can actually see these from the air when you’re in one of the low-flying bush planes which transport guests from camp to camp). 

The harvester ant feeds primarily on seeds which the colony tirelessly gathers at night when the air is cool.  The seeds are brought back to the nest where the outer husk is removed and dumped in a large mound at the entrance.  The seeds then go underground where they rot and develop a fungus which the ants eat. During periods of extreme drought seeds become scarce and they begin to cannibalize their own.  Interestingly, the smallest ants will eat the largest:  they suck all the fluids and then dump the hard desiccated remains outside the entrance along with the seed husks.  Tiny but mighty.

Finally, we saw the Marimburi or warrior ant.  We had moved further north to a camp called Sarara, which is nestled in the Mathews range on the other side of Mt. Kenya and is run by the Samburu tribe (the Samburu are distant cousins of the Massai and are also herders).  The camp sits alone amidst almost one million acres of wild land and sleeps only 18 guests.  We were on our way back from a drive when Russ spotted a mass of activity on the ground.  Large black ants about the size of giant carpenter ants were scurrying down the hill.  Our guide Mark told us that this ant was originally named for a particularly skilled fighting tribe from the Congo.  He explained that the ants we were watching were completing a successful raid on a nearby termite mound. 

As we leaned down for a closer view we could see that each of the large ants was indeed carrying something in its front pincers:  termite larvae!  We watched as the formation raced across the path and disappeared beneath a bush.  Seconds later, another wave emerged.  Again, pincers were laden with the stolen larvae.  They moved with amazing speed and precision.  Mark pointed out that not all of the carried items were larvae—these ants never left a dead or wounded companion behind.  He pointed to the smaller ants in their midst.  These ants are the first to enter during a raid and usually sustain the most damage.  Their larger compatriots will pick up and carry any fallen or wounded back to their own nests.  Incredibly, Mark told us that these ants also use surveillance:  they send an advance spy party of four ants before every raid.  Only when these scout ants have returned to the nest and communicated the location of the termites does the squadron of attack ants assemble and move out. They were tiny Marines!


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