archived as http://www.stealthskater.com/Documents/Driver_Ants.doc
Nature's Most Awesome Army
[StealthSkater note: I did a Google search for "Army Ants" and "Driver Ants". Hundreds of articles
were referenced including the following … ]
Out There: Lord of the Flies
And the bees and the wasps and all the other biting bastards that walk upon the Earth
by Tim Cahill , Outside magazine, July 1998
The bug scream is a distinctive human sound. It is characterized not by volume or intensity or
duration, but by the very sound itself. A kind of high-pitched, astonished loathing that combines the
"eeewww" of disgust with the "aaahhh!" of abject terror. Eeewwwaaahhh! Every human has produced
a bug scream at one time or another. And every human has heard someone else generate such a sound.
Here is the First Rule of Vermin Shrieking: When a human being other than oneself bug-
screams, the sound is -- by instinctual definition -- funny. Cahill's Corollary to the First Rule is this:
Bug screams screamed by individual human beings are not funny to the individuals screaming.
Not that I consider myself squeamish. Quite the contrary. I've actually eaten bugs. More
frequently, bugs have eaten me.
Not too long ago, for instance, I was walking across the Congo Basin in company with an American
scientist, a filmmaker, 3 Bantu villagers, and 13 pygmies. It was hot. The forest contained what I
imagined to be the "better" part of all the noxious bugs that have ever existed upon the face of the Earth
including bees and wasps, which I found particularly annoying because the creatures with stingers
tended to congregate on me to the exclusion of my expeditionary colleagues.
Why me? The scientist -- Michael Fay of the Wildlife Conservation Society -- said, in effect,
"Because you're the big fat sweaty guy." He explained that all living organisms need salt and that one of
the factors limiting the abundance of life in the swampy forest is the lack of salt. The fact is that I was
taller than Michael by several inches, more than a foot taller than the largest pygmy, and I outweighed
everyone by 50-to-100 pounds. I also sweat a lot. I was, in effect, a walking "salt dispenser" -- an
ambulatory fountain of life.
There were at least half-a-dozen different kinds of bees in the forest. And every time I stood still for
a minute-or-more, a score of them took up residence on my drenched and sweaty T-shirt. Here, I
thought, is an opportunity to observe Nature in action. One interesting bee fact I learned is this: The
little bastards generally only sting in response to dorsal pressure. If, for instance, you happen to be
setting up your tent and there are 50-or-60 bees sucking salt off your T-shirt, they will not sting unless
you touch them on the back. For this reason, I found it necessary to walk with my arms held out stiffly
from my sides and to move in a slow, somewhat robotic fashion.
The problems occurred when salt-thirsty bees crawled up under the sleeves of my shirt toward the
armpits -- headed straight for the "fountainhead", as it were. Then no matter how robotically I moved
my arms, there was some small dorsal pressure involved. It was worse when they crawled up the legs of
Aside from the bees, there were tsetse flies which can cause sleeping sickness -- a disease
characterized by fever, inflammation of the lymph nodes, and profound lethargy. Sleeping sickness is
Moreover, the insects that carry the disease are intensely annoying creatures. They are long, thin,
malnourished-looking flies with skinny iridescent wings. And the ones I encountered moved so slowly
that I could actually bat them with a palm while they were in flight. Occasionally I'd get a really good
whack at one. It would seem to falter in its aerodynamics, then wheel about in a lopsided loop as if
woozy and staggered. But it would keep coming at me. Once it was dazed, I could sometimes pop it 3-
or-4 more times using both hands -- whap, bap, whap, bap -- just like working out on a boxer's speed
bag. The fly would back off … lose altitude … and then -- as through an act of will -- seem to straighten
up and fly right, zeroing in on me yet again, willing to take any amount of punishment simply to get its
filthy, disease-ridden, bloodsucking proboscis into my flesh. It was like fighting "Rocky" in the movies.
Tsetse flies never quit.
Worse, you can't swat them on your skin like mosquitoes. They have some kind of dorsal radar and
when threatened from above, they simply fly away.
A pygmy who looked a little like a short, dark version of Jerry Lewis showed me the way to kill
tsetse flies. Simple thing. Put a hand on your body some small distance from the fly and roll right over
the son-of-a-bitch from the side, like a steamroller. This produces a nasty swatch of blood and bug guts
… and is immensely satisfying!
Aside from the tsetse flies, we often encountered aggregations of fire ants, which are small and red
and prone to swarming gang-stings. They frequently looked like seething hillocks of red fungus on
downed trees that crossed our path. Sometimes while walking along a nice, wide elephant trail near such
a tree, I'd see pygmies in the column ahead suddenly break into a strange hop-step sort of polka as they
attempted to shake the fire ants off their bare feet and legs. The convention was to yell "formi (ants)".
In fact, watching someone out ahead do the "Fire Ant Polka" was all the warning anyone ever needed.
It's awfully funny. That is, when someone else is dancing it.
There were also driver (army) ants of the type with 2-inch long pincers. It is said that various
native people in Africa use driver ants to stitch up wounds. It is supposed to work like this: The ant is
held in the fingers and positioned with a pincer on either side of the wound. The ant then bites as ants
will -- the difference in this case being that driver ants won't let go. At this point, one simply twists the
nasty little body off the pincers. Instant sutures!
Among the most unbearable of the insects was a kind of stingless bee -- like a fruit fly, actually --
called a melipon. Michael Fay said the word came from the Greek: "meli" meaning honey, and "pon"
meaning -- I think -- incredibly annoying little sons-of-bitches. They arrived out of nowhere in clouds,
so that suddenly every breath contained hundreds of melipons. They crawled into my ears and nostrils.
Every time I blinked, there were several melipons ejected from my eyes, rolled up and kicking their
fragile little legs, like living tears rolling down my cheeks.
Sometimes we crossed orderly columns of termites -- thousands of them -- marching along on some
destructive mission or another. At night, they would crawl in formation under my tent. I could hear an
unnerving <clicking> and <clacking> sound. Termites … moving under my body in their thousands …
all of them snapping their hideous little jaws.
Nevertheless, none of these creatures ever caused me to produce a single distressed sound beyond
"owww". Halfway through my Congo walk, I believed myself almost immune to that universal human
frailty -- the bug scream. Vermin shrieking was something that other people did. And they did it for my
I am, in fact, guilty of arranging certain situations designed to test and trigger the First Rule of
Vermin Shrieking. It was high school speech class, and here was my evil plan for the final assembly of
my final year. There would be 400 students in the new auditorium -- every seat filled -- and I intended to
hear them scream.
We'd use the impressive new spotlights designed for stage plays. The best student actor I knew --
and the only one I could trust to go along with me on this deal -- was Dave Hanson, who would walk
onstage wearing a funereal black suit. Stepping up to the podium under a single spot, Dave was to
solemnly open a book, fix the audience with his best Vincent Price stare, and begin reading Edgar Allan
Poe's merry little contemplation of corporeal decomposition after death entitled "The Conqueror Worm".
We knew what would happen. My fellow students -- fearing Culture -- would no doubt fidget for a
bit. The poem postulates a throng of angels sitting in a theater. On the poetic stage, Poe has positioned
"mimes, in the form of God on high."
At this point, we'd begin to shrink the spot on Dave. The auditorium would become very dark as he
dug down deep for his best shuddery bass voice on the verses we needed to really hammer home in
order for the prank to work.
The mimes in the poem are -- good Lord! -- human beings. In their midst, Poe has "a crawling
shape intrude". Blood red, it writhes, it writhes. "The mimes become its food," and it -- the blood red
crawling shape-- is "in human gore imbued."
Dave could read that well, I knew. He'd pull the audience into the horrid realization of what this
poem is all about. The last verse begins: "Out -- out are the lights -- out all!" Which is when we'd kill
the spot altogether, leaving the auditorium in total darkness while Dave gravely intoned the last lines,
which are all about the poetic angel audience sobbing heavenly tears because they realize "That the play
is the tragedy, 'Man,' / And its hero the Conqueror Worm."
Here, timing was important. We needed to hit them during the silence following Dave's recitation,
but before the muttering and mumbling began. I had 3 confederates all lined up for the nonverbal punch
line. In the darkness, the 4 of us would run down the aisles of the silent auditorium, tossing out great
handfuls of cooked spaghetti, still warm and a little damp. The spaghetti flingers all had a 2-word line, a
terror-filled scream, to be repeated as necessary: "THE WORMS... THE WORMS..."
Do it right and everybody would scream. 400 flat-out bug screams or -- more precisely -- worm
screams. Different creature, same sound.
One problem: Along with the rest of my worm-tossers, I needed a pass to be in position at the back
of the auditorium. A damn fine teacher named Fred Metzner demanded to know why the 4 of us wanted
these special passes. He wouldn't accept "it's a surprise" as an explanation. Fred Metzner had learned
not to trust "student surprises".
And so my plan was foiled at the last moment. Mr. Metzner described the idea as "juvenile", though
I thought it was a good deal more mature than that. It was adolescent at the very least.
One night -- several weeks into the Congo walk -- I was just dropping off to sleep sometime around
ten in the evening when a half-pound centipede fell from the tent ceiling onto my naked, sweaty chest
with an audible [plop!]. Later under my headlamp, I was to discover that it was not one of the poisonous
ones. Just a normal Congo Basin jungle centipede and "only" about the size of an ordinary polish
sausage. It looked naked and pink and was curled in on itself like something the dog left on the lawn.
Under a flashlight, the bug wasn't something you'd necessarily scream about.
But half-asleep and in the dark, I had no idea what it was. Just something wet and heavy that
seemed to have been dropped from a great height. I shouted "eeewwwaaahhh!" I believe that I shouted
"eeewwwaaahhh!" several times in the darkness -- a crescendo of half-awake terror. And when I
brushed at my chest with blind, fluttering hands, I suddenly felt the heavy worm-like thing just above
my wildly beating heart and swept it to the side. I said "eeewwwaaahhh!" several more times as I leapt
to my feet … nearly stuck my head through the fabric of my tent … fell down somewhere near where
the unknown creature had to be … rolled over … and finally came out of my tent like a scorched cat, all
the time saying "eeewwwaaahhh! eeewwwaaahhh! eeewwwaaahhh!"
The pygmies -- all 13 of them -- were over in their camp, maybe 50 yards away. I could hear their
battery-powered shortwave radio blasting out static-ridden music. The sound, as usual, was turned up
into that range of irritating distortion in which it is impossible to tell reggae tunes from English
madrigals. Pygmies -- I had learned on my Congo walk -- listen to the radio all night long. And they
will always sacrifice fidelity to volume.
I had started out on this long jungle trek determined to get close to the pygmies -- to understand their
lives, their hopes, their dreams, their music. Most of all, I wanted to absorb a small measure of their
knowledge of the forest. But they kept the radio on all night, never seeming to sleep, and I generally
camped some distance away just out of earshot.
So it was possible they hadn't heard me bug-screaming.
But no! they were shouting and howling among themselves. Aand the howls were those of high-
pitched, helpless laughter.
"What?" one of them called out to me in French, our only common language. I think it was Kabo --
as handsome as a homecoming king and one of the leaders. "What has happened?" he called.
I didn't know the French word for "centipede". I don't know much French at all. But the word for
"insect" isn't particularly difficult for an English speaker.
"Insecte," I said.
Kabo strolled over, along with half -a-dozen other pygmies. I had scooped the centipede up onto a
machete, using my notebook to avoid touching the thing, and was about to dump it -- alive! -- a good
distance from my tent. But the pygmies had to examine the creature that had caused me to say
"eeewwwaaahhh!" several dozen times.
They aimed their one flashlight on the machete. The beam was very dim and yellow in color. The
pygmies said some words to one another in Sangha (their native language), looked up at me, and --
unnecessarily, I thought -- began laughing again. They shook my hand and slapped me on the back and
laughed until tears came to their eyes. It was, I thought, incredibly juvenile behavior!
Later that night, I could hear them in their camp, shouting over the static on the radio. They used the
word mundele ("white man") which has about the same connotation that the word gringo has in Latin
American countries. It is sometimes merely descriptive and neutral of nuance. And sometimes it can
mean "greenhorn", "oaf", "imbecile", or "doofus". The meaning depends on context. In this case, there
would be silence for 10-15 seconds … then one of the pygmies would say mundele -- meaning me -- and
the rest of them would begin howling with a kind of hilarity that I believed to be entirely inappropriate
to something as 'human' and unaffected as a few dozen simple bug screams.
It was in those moments of sweaty humiliation that Cahill's Corollary to the First Rule of Vermin
Shrieking was born, screaming.
WHAT LIVES IN A BIVOUAC, IS ALMOST COMPLETELY BLIND,
AND DEVOURS UP TO 100,000 ANIMALS A DAY?
ANSWER = AN ARMY ANT COLONY
Army ant colonies -- like most ant colonies -- have a
single queen ant who lays all the eggs and female workers that
tend the young and collect food for the colony. One of the
things that make army ants even more interesting is how much
food they require and how they get it.
Army ants belong to one of the subfamilies of ants called
the Dorylinae after the Greek word meaning "spear". There
are approximately 150 species of army ants found mostly in
the tropical and subtropical regions of Central and South
America. There are also 100 other species in the "Old World" Eciton burchelli soldier
(Africa, Australia, and the Orient) sometimes called
"Army Ants" but more usually known as "Driver Ants".
3 incredible things you should know about Army Ants:
1. They have HUGE colonies
For example, one species -- Eciton burchelli from South America -- may have a colony containing
over a million ants. Each colony consists of a single (wingless) queen, a brood of developing young,
and a large population of adult workers.
Only the Queen and the males have eyes, the workers are all blind and rely on chemical trails to find
their way around.
Some Driver Ant colonies contain over 20 million individual ants!
2. They are carnivorous!
They feed on other arthropods, mainly other insects which they capture by highly organized group
raids. Some species have been seen to eat small vertebrates such as lizards and snakes. The amount of
food caught is tremendous. Workers of Eciton burchelli may capture more than 100,000 arthropods a
day to feed the colony!
The workers charge along the surface of the ground or along underground channels (depending on
the species) and follow chemical trails laid down by the ants themselves. All the time, huge soldier ants
with massive jaws watch over the workers and protect them. The jaws of the soldiers are so huge that
they are unable to feed themselves and must rely on workers to give them all the nourishment they need.
Different army ant species use different types of raiding pattern. The 2 types of pattern are column
raids and swarm raids. Eciton hamatum and Eciton burchelli are the 2 species of army ant that have
been studied the most. Both species begin raiding at dawn with ants pouring out of the nest/bivouac but
use different raiding systems.
E. hamatum is a 'column raider'. The ants produce branching
trails by dividing into small foraging groups, forming a tre- like
pattern (see Fig 1). Each trail has a 2-way stream of ants running
along it -- some ants are advancing whilst some are returning with
prey. The ants may travel over 350 meters from the bivouac in a
raid, though it depends on the type of terrain and the condition of the
colony. They often invade the nests of other social insects (but not
other army ants!!) and steal their brood.
E. burchelli is a 'swarm raider'. Great crowds of raiders sweep along the
ground like a dragnet flushing out a huge variety of prey (see Fig 2). A fan-
shaped network of columns trail behind. And in the rear, there is a base
column connecting the raiders with the bivouac. 'Swarmers' have stronger
bites and more potent stings than 'column raiders'. And they attack a wider
range of prey, including hard bodied arthropods.
Driver ants have been known to kill and dismember chickens, goats and
even pigs if the animals have been injured or unable to escape the marauding
3. They migrate
Due to their large colony size and carnivorous habits, army ants must migrate in order to find enough
food. The ants form only temporary nests and after raiding. the whole colony emigrates to a new nest
site unless it is in a "statary" condition (i.e., the larvae in the colony are entering a pupal stage by
spinning their cocoons and the enormous queen is laying eggs).
The "nests" of army ants are not like those of other ants. They are made out of the ants themselves!
They are therefore referred to as "bivouacs" describing the resting state of the colony rather than a
physical nest structure. The ants cluster together to form walls and fasten onto each other using their
mandibles and claws on their legs.
So next time your picnic is interrupted by a few black ants, consider yourself lucky that you don’t
live in the tropics where you could be carried off as well as your sandwiches!
-- by Zoe Masters
"The Driver Ants" by Leonora and Arthur Hornblow
The most famous fighters of all the ants are the driver ants of Africa. Most ants live in one place.
But the driver ants are almost always on the move. Sometimes millions of driver ants march through the
country together. They eat every insect, bird, and small animal they can find. They will eat large
animals and people who cannot get away. Even elephants run from an army of terrible driver ants!
One thing that driver ants run away from is strong sunshine. It will kill them. That is why they
march at night and on cloudy days. The marching ants may come to a stream. They cannot swim well.
But they can do a very strange thing. Some of them take hold of a root or a bush with their strong jaws.
Other ants take hold of these ants. Soon there is a "rope" of ants. The water carries it to the other side.
Now it is a bridge. The rest of the ants march across it. On they go, looking for food.
They will not eat some things other ants love. They do not like sugar, bacon, or bread. So if you
have a picnic in Africa, do not worry about these ants eating your sandwiches. Worry about their eating
One of the most fearsome groups of animals in the rainforest are not jaguars, snakes, or crocodiles
… but ants. Many ants in the rainforest can inflict excruciatingly painful bites and stings on the unwary
forest visitor. The 24-hour ant of South American is regionally famous for its bite that can leave the
victim in terrible pain for hours. However, ants also happen to be one of the most interesting and
important animals in the forest as exemplified by 2 ant types: Army Ants and Leafcutter Ants.
Army Ants of the New World have long been depicted in fictional movies and books as a
marauding force that threatens everything in their path including people and entire villages. This is
hardly an accurate scenario. Some rainforest peoples actually welcome the periodic visitations by army
ants to clear their hut of unwanted resident pests.
In addition, forest peoples have been known to use large soldier ants (also soldier leaf-cutter ants)
for medical purposes. The ant is picked up by its body -- with its powerful mandibles open -- and placed
over an open wound where it is allowed to clamp the wound closed. The native then twists the head off
and the jaws remain as a temporary, natural suture.
Although soldier army ants are formidable with their huge jaws, the majority of ants in a given
column are medium sized worker ants. The sheer numbers of these ants enable a column to overtake
animals that normal-sized colonies would not. There are reports of tethered animals being devoured.
But most of the column's prey consists of other invertebrates. The column scares up many insects that
usually remain hidden or camouflaged during the day. Enough of these insects are scared up to support
numerous species of birds that follow ant columns and feed exclusively on the insects. Dependent on
the antbirds are ithomiine butterflies which feed on their nitrogen-rich droppings. Unlike other
butterflies which are restricted to food reserves built up during their caterpillar stage, these ithomiine
butterflies are able to live and reproduce for months thanks to the proteins gleaned from the bird
droppings. The ithomiines are safe from predation by the antbirds because as caterpillars, they feed on
leaves containing poisonous alkaloids giving the adult butterflies an unpleasant taste. Other moths and
butterflies mimic the warning coloration of ithomiine butterflies to afford themselves with protection.
Other species benefit from the army ant columns. Trachinid flies wait in vegetation above the ant
column for grasshoppers to appear. When one does, the fly lays an egg on its body. The egg hatches
into a larvae which burrows into the grasshopper and devours the insect from the inside. Certain insects
including wasps, beetles, and millipedes are capable of chemically mimicking the odor of army ants so
they are undetectable as they move through the column since most ants have very poor vision and can
only really distinguish between light and dark. These creatures are able to get free meals in the form of
prey exposed or captured by the column.
The Old World equivalent of army ants are the driver ants, which are blind and move in massive
armies (20 million) under the leaf litter.
June 13, 2001
Before we ever came to Africa, we heard the stories about "driver ants" and thought they sounded
pretty awful and a big headache. Becki Thompson told us stories of how the cockroaches start
squeaking when the driver ants come. That sounded a little amusing and a bit creepy. We had seen the
lines of them across roads and sidewalks -- coming from or going to the jungle -- and stood from a
respectful distance to see their big pinchers and watch them off on their mission to wherever. Now we
can say that they ARE truly a headache! But not quite so awful as we imagined them to be (as long as
you don't get bit!)
With dry season here, the ants are looking for water and a place to hibernate. They have been on the
move quite a lot during the last several weeks. We have seen quite a number of their marching columns
down the road from us and up at the visitors' apartments. Last night when we were up at Dave and
Becki Thompson's house for a station meeting, Al stepped into some of them in the dark and was tearing
them out of his sandals and off his legs by the time we got into the house. I don't think he got any of the
big ones on him because he wasn't yelling too much, just smashing his sandals on the floor and brushing
off his legs pretty good.
This morning when we got up, of course the first room we visit is the one with the most water. And
what should I see swarming all around the base of the toilet but ants everywhere. Hmmm... "Hon, come
look at these... They almost look like driver ants..." Al came and looked, went outside, then came back
in quickly and grabbed a can of "Elf" (bug spray) and was outside again spraying the whole can it
seemed. They were swarming all around the foundation underneath the bathroom and our bedroom.
There was a hole in the brick where they had come into the bathroom, so he was waging war on
them. We think probably detoured them at least. So he is now armed with his Hudson sprayer and a
bottle of "Daemon EC" that he brought with us from Chico, and he is spraying the entire perimeter of
our house. I am hoping to go out with my tweezers and a film canister a little later and collect a few
specimens for Mike Emmons' biology class. So please! don't anyone "spill the beans" to U.S. Customs.
Seriously, we have gained a new respect for ants that we never had before. Here in Africa, they are
the serious garbage collectors. If you smash a bug, within 5 minutes it is covered with ants. Within
half-an-hour, there is no more bug! And we have ants here in every size and description that you could
imagine. From tiny red ones who run around like they're on speed, to the huge drivers with the giant
pinchers whose bite feels like a jolt of 220 electricity (so I'm told -- so far I have been very careful!).
We thought you'd enjoy experiencing vicariously one of Bongolo's little thrills! The only problem is
that now I am going to be feeling "things" crawling on me all day!
-- Al and Deb
Some ants in Africa are carnivorous. Driver ants perform daily raids in swarms that resemble
labyrinths of thick black rope. As they advance across the forest floor, they engulf everything in their
path. Colonies can be composed of up to 22 million workers. When they capture prey, it is thought that
they act together as one “animal” with millions of mouths. Using the powerful bite and shearing action
of their mandibles, they have been known to feast on one of the World’s largest serpents -- the African
python -- when it lies powerless digesting its food.
-- Nora Gallagher
In the kitchen as I make lunch, dozens of bees hover around me. I think for the umpteenth time how
this is truly the most inhabited place I've ever lived! Every inch is taken up by some creature. It's like
the movie "Microcosmos" times 10.
A week-or-so ago, the numbers of one particular species were really brought home to us … literally!
One night as we all prepared to go to bed after a lengthy meeting, Andrea discovered that hordes of
driver ants had homed in on her hut and were teeming around her steps and concrete blocks -- apparently
intent on entering and taking over. This happens sometimes when thousands of these ants -- which have
quite a painful bite, I've experienced it a few times -- take over a space in search of food. They are in
hunting mode. Some people have woken up to find themselves covered with the things, which eat
through their bed netting and swarm over them. Andrea was, of course, unhappy about this. And we
watched as she hurriedly filled a huge watering can with kerosene, dousing many of the ants, and
circling her house with it. Kerosene is the only thing that can deter them.
She decided not to sleep in there that night and made a bed up for herself on the camp's central
paillote below. Our skin crawling, Mya and I went over to our hut about 40 feet from Andrea's and
realized with horror that the waves of ants were extending to our home and were about 3 feet from
entering. There were tens-of-thousands of them, coiled in these long undulating lines that wrapped
around a corner of our hut and moved ever closer. We dashed to get kerosene and -- just in the nick of
time -- drenched the borders of our concrete floor with it.
We kept an eye on them for the next 45 minutes-or-so. Temporarily confused and disoriented, the
swirls of ants turned back on their paths, ran in circles, hurried this way and that. Then finally in a
concerted movement, they headed off towards the forest. Mya and I shuddered to think of how things
might have gone if we hadn't had that meeting and therefore had been in bed earlier, unaware of the
advance of this copious army. Yikes!
The ant society
Both ants and termites (white ants) live in large colonies consisting mostly of sterile, wingless
workers, dedicated to the efficient production of winged reproductive castes which fly off to found new
colonies. Both ant and termite colonies have one enlarged 'queen' -- sometimes grotesquely enlarged.
In both ants and termites, the workers can include specialist castes such as 'soldiers'. Sometimes these
are such dedicated fighting machines, especially in their huge jaws (in case of ants, but 'gun-turrets' for
chemical warfare in the case of termites), that they are incapable of feeding themselves and have to be
fed by non-soldier workers.
Terror of the jungle?
Both driver ants and army ants have exceptionally large colonies. Up to a million in army ants, up
to about 20 million in driver ants. Both have nomadic phases alternating with 'statary' phases, relatively
stable encampments or 'bivouacs'. Army ants and driver ants -- or their colonies taken together as
amoeba-like units -- are both ruthless and terrible predators of their respective jungles. Both cut to
pieces anything animal in their path. And both have acquired a mystique of terror in their own land.
Villagers in part of South America are reputed traditionally to vacate their villages "lock, stock and
barrel" when a large ant army is approaching and to return when the legions have marched through,
having cleaned out every cockroach, spider, and scorpion even from the thatched roofs. I remember as a
child in Africa being more frightened of driver ants than of lions and crocodiles.
No, driver ants are not really the terror of the jungle. Although the driver ant colony is an 'animal'
weighing in excess of 20 kg, possessing on the order of 20 million mouths and stings, and is surely the
most formidable creation of the insect world, it still does not match up to the lurid stories told about it.
After all, the swarm can only cover about a meter of ground every 3 minutes. Any competent bush
mouse -- not to mention man or elephant -- can step aside and contemplate the whole grass root frenzy at
leisure, an object less of menace than of strangeness and wonder...
The strangeness and wonder
As an adult in Panama, I have stepped aside and contemplated the New World equivalent of the
driver ants that I had feared as a child in Africa, flowing by me like a crackling river. I can testify to the
strangeness and wonder. Hour-after-hour, the legions marched past, walking as much over each others'
bodies as over the ground while I waited for the queen. Finally she came …
… and hers was an awesome presence. It was impossible to see her body. She appeared only as a
moving wave of worker frenzy -- a boiling peristaltic ball of ants with linked arms. She was somewhere
in the seething ball of workers, while all around it the massed ranks of soldiers faced threateningly
outwards with jaws agape. Every one was prepared to kill and to die in defense of the queen. Forgive
my curiosity to see her. I prodded the ball of workers with a long stick, in a vain attempt to flush out the
queen. Instantly 20 soldiers buried their massively muscled pincers in my stick -- possibly never to let
go -- while dozens more swarmed up the stick causing me to let go with alacrity.
I never did glimpse the queen. Bt somewhere inside that boiling ball she was -- the central data
bank, the repository of the master DNA of the whole colony. Those gaping soldiers were prepared to
die for the queen. Not because they loved their mother. Not because they had been drilled in the ideals
of patriotism. But simply because their brains and their jaws were built by the genes stamped from the
master die carried in the queen herself. They behaved like brave soldiers because they had inherited the
genes of a long line of ancestral queens whose lives -- and whose genes -- had been saved by soldiers as
brave as themselves.
We had only been in Brewaville a few days when we had our first experience with driver ants. It
was late at night and we were in bed when we heard a loud shouting outside. All of us flew out of bed
and into our clothes. The missionary shouted to us, "The driver ants have come!" We didn't know what
"driver ants" were. We had seen ants before, so what was the big deal?
But we had never, never seen ants like these! They came by the millions. It was an organized
military attack by an army of voracious, carnivorous beasts intent on devouring everything in their path.
Their black bodies were about a half-inch long and very hard. They were vicious and aggressive. I
found my distress that these meat-eating mini-monsters can bite like bulldogs and hang on just as
tenaciously. If you pull them loose from your skin, a little piece of skin goes with them in their jaws.
In the darkness of the night, I looked for the advancing horde that had already invaded the penned-in
area where chickens, rabbits, goats, and pigs were kept. The Liberians frantically spread kerosene
across the path of the ants and set fires in order to divert their migration away from the house and the
This battle continued for hours. As I watched the war from what I thought to be a safe vantage
point, I suddenly experienced a series of stinging bites on my legs. I looked down … and I was standing
right in the ants. They had begun crawling up my legs, intent on consuming me.
I commenced a dance that was not in the Holy Ghost. I performed steps that were new to me and for
which I had received no formal training. I realized that it was time to flee the scene. I made a dash for
the privacy of our assigned bedroom where I could get my pants off and pick the black bulldogs off me.
After I dispatched my assailants and got my trousers back in place, I went back outside to see how this
epic battle was going. This time, I was more careful in choosing a secure observation point.
After several hours of serious effort, the ants were diverted to other targets. None of the livestock
was lost, and the ants did not get into the house. They could be a serious threat to life if a person was
unable to escape them. Finally, we crawled back into bed in the wee hours of the morning.
The next several days were calmer, and we spent our time getting oriented to our surroundings.
Unfortunately, not all discoveries are so much fun as Simon gets the find of the day award for
discovering a column of driver ants crawling through his tent at 2:30 am. Driver ants -- for the
uninitiated -- move through the forest in massive columns, devouring every creature in their path
including mammals if they're too slow or stupid to get out of their way. They have razor-sharp
mandibles that can draw blood in a heartbeat.
Luckily, only the "minor" worker ants -- which are smaller than the major workers -- were able to
work through the mesh in Simon's tent. But they still gave him several nasty bites before he commenced
It is probable that progenitors of rain forest legionary ants (Dorylinae) were able to follow the rain
forest termites across a Bering Sea bridge on the moist rain forest coastal regions sometime during the
Cretaceous eventually -- most likely near the close [Schneirla]. However, their progress must have been
very slow to migrate. This is because they do not send off female mating flights but reproduce by
colony fission. Therefore they could not cross a swamp or river unless a raft happened to touch down on
the opposite side, which would be a very rare event for a subterranean insect fielding large colonies, or
an oxbow was cut off.
Leafcutting ants can bore under a river in the current world and thus presumably provide a path for
Dorylines in South America [Branner (1910), p473]. But it is doubtful that they had such an attribute in
the Cretaceous, or leafcutters even existed then. Dorylines could not inhabit a raft for more than a
couple of days, for they starve to death in a short time without food [Holldobler & Wilson (1990),
African driver ants can form a ball and float the whole colony on water [Wheeler 1910]. I
suspect that underground driver ants cannot. That last trait may have helped them reach Africa. But
such a ball almost certainly could not have crossed an ocean and they never reached Madagascar, which
last was no doubt additionally ruled out because of no rain forest on the opposite African shore.
Tales of a Deadly Army
Living in colonies of 600,000-or-so, tales of South American army ants are legendary. But many of
them are true. These tiny creatures are formidable predators, but only if they work together. Normally,
great columns of these nomadic ants march and bivouac through lowland tropical rainforests from Peru
to Mexico. They are capable of killing every living thing in their path.
Any animal big or small unable to flee -- or even an injured person -- is attacked and within a few
hours us stripped to the bone. There was an incident in Central Brazil in which a column of these
insects -- measuring about 1 mile by half-a-mile -- was seen moving towards the town. Immediately,
the police and the townsfolk became active and tried to stop the ants. But they failed until flame-
throwers were used. In the struggle, the police chief and few of the townsfolk lost their lives to these
The success of army ants lies in their ability to work as one gigantic super-organism. Foraging
parties follow scent trails left by scouting soldier ants (a group within the colony that protects large
raiding parties of worker ants of the same colony). These powerful scents also act as territory markers
and are recognized and avoided by other colonies of army ants. While on a food-finding expedition,
successful scouts head back down the trail and encourage any ants they find en route to continue
onwards by pummeling their antennae and offering them a blob of regurgitated food.
Food mostly consists of hard-bodied creatures such as other insects, spiders, and scorpions. The
colony is constantly on the move to find new supplies. Movement is not constant. Instead, a 15-day
"nomadic" phase alternates with a 20-day "sedentary" phase. After a couple of weeks traveling through
forests, the colony comes to a halt and sets up a semi-permanent camp. It stays there for about 20 days
while the queen lays her latest batch of 50,000-100,000 eggs. In the mean time, the workers go out to
scour the forest for food. They forage in a fixed pattern, radiating from the camp like the spokes of a
wheel. On Day One, the columns head off in one direction. And the next day, they take a compass
heading exactly 123 degrees in another direction. By varying their direction in this way, they ensure
that they do not comb the same piece of forest twice.
When the eggs hatch and a new army of mouths must be fed, the colony returns once more to a
nomadic lifestyle. At dawn, columns of workers -- guarded at intervals by large-jawed soldiers -- set out
from the daily bivouac and go hunting. Maintaining a constant compass heading, they travel at about 15
yards-per-hour over a distance of 200 yards-per-day. Scuttling to-and-from the bivouac where the queen
and her entourage spend the day, there can be over 200,000 ants in a column. Side streams split off
from the main column and spread out to form a raiding front up to 20 yards wide. Streams are not a
barrier. Workers simply interlock legs and form a living bridge over which the colony can pass. If
caught in floods, the colony rolls into a large ball and floats to safety.
In the evening, the queen’s bivouac unravels like a ball of wool and follows the route of the day’s
raiding column. They travel under the cover of darkness for about 8 hours to the next bivouac site --
about 90 yards along the trail -- setting up temporary camp before dawn breaks.
In some parts of the World, army and "driver" ants -- another species with almost same habits -- are
not feared but welcomed. If columns of ants are heading for human habitation, local village folk will
just leave until the ants have passed through. The ants strip the houses of vermin, snakes, scorpions, and
These ants -- sometimes called army ants -- like the driver ants of Africa move in big bodies.
They destroy or make prey of every living thing that is unable or unwilling to get out of their path in
time. They run fast, and everything runs away from their advance. Insects form their chief prey. And
the most dangerous and aggressive lower-life creatures make astonishingly little resistance to them.
Miller’s attention was first attracted to this army of ants by noticing a big centipede -- 9-or-10 inches
long -- trying to flee before them. A number of ants were biting it. It writhed at each bite, but did not
try to use its long curved jaws against its assailants. On other occasions, he saw big scorpions and big
hairy spiders trying to escape in the same way, and showing the same helpless inability to injure their
ravenous foes, or to defend themselves. The ants climb trees to a great height -- much higher than most
birds’ nests -- and at once kill and tear to pieces any fledglings in the nests they reach.
But they are not as common as some writers seem to imagine. Days may elapse before their armies
are encountered, and doubtless most nests are never visited or threatened by them. In some instances, it
seems likely that the birds save themselves and their young in other ways. Some nests are inaccessible.
From others, it is probable that the parents remove the young.
Miller once in Guiana had been watching for some days a nest of ant-wrens which contained young.
Going thither one morning, he found the tree and the nest itself swarming with foraging ants. He at first
thought that the fledglings had been devoured. But he soon saw the parents -- only about 30 yards off --
with food in their beaks. They were engaged in entering a dense part of the jungle, coming out again
without food in their beaks, and soon reappearing once more with food. Miller never found their new
nests. But their actions left him certain that they were feeding their young, which they must have
themselves removed from the old nest. These ant-wrens hover in front of and over the columns of
foraging ants, feeding not only on the other insects aroused by the ants but also on the ants themselves.
This fact has been doubted. But Miller has shot them with the ants in their bills and in their
stomachs. Dragonflies in numbers often hover over the columns, darting down at them. Miller could
not be certain he had seen them actually seizing the ants. But this was his belief. I have myself seen
these ants plunder a nest of the dangerous and highly aggressive wasps, while the wasps buzzed about in
great excitement but seemed unable effectively to retaliate. I have also seen them clear a sapling
tenanted by their kinsmen -- the poisonous red ants or "fire ants". The fire ants fought and I have no
doubt injured-or-killed some of their swarming and active black foes. But the latter quickly did away
with them. I have only come across black foraging ants. But there are a red species. They attack
human beings precisely as they attack all animals, and precipitate flight is the only resort.
What kind of ants can survive a flood?
Colonies of driver ants -- a type of sightless ant found in Africa -- can survive a flash flood and
even travel for days by water! Driver ants are known for traveling in huge columns. When they are
caught by a flash flood, they pack themselves into a huge sphere with the soldiers on the outside
protecting the workers, eggs, and queen on the inside. Driver ants can survive like this for days until
they wash ashore!
But all creatures have reason to fear one particular African ant, whose cavernous shafts descend 6
feet-or-more into the ground. These ants live in the biggest single colonies of any animal on Earth with
up to 20 million sisters operating like a huge monster with a monstrous appetite to match.
These are driver ants. When they march, nothing in their path is safe. They've been known to kill
tethered horses, human babies, and have even been used to execute criminals. Soldier ants stand guard
over the marching column. The river of ants divides, spreading out over the forest floor. Few victims
escape once the ants get a grip. Millions act like a fearsome super-organism emerging from its lair,
sending out long tentacles of marching workers to engulf its prey.
A giant slug seems an unlikely target -- its thick slime a sticky trap. But the persistent ants
overwhelm the slug. They have a neat trick to soak up the slime, sticking tiny fragments of leaf and soil
all over the slug. The soldiers now get to work, slicing it up like a beached whale with their powerful
jaws. The ants then release their trapped sisters. It's all-for-one and one-for -all.
The relentless army marches on. Those that can leap for safety, while others watch from above as
hordes of cockroaches and other insects are driven ahead of the raid. Many that escape the ants run right
into the path of shrikes and other birds that feast on fleeing insects. There's no safety in fleeing upwards
for the ants follow.
A praying mantis is more than a match for just a few ants. But with so many attackers, it can't eat
them fast enough. They carry the mantis off piece-by-piece. Several ants share the heaviest loads.
Workers labor to keep the trail clear. Soldiers form living archways over the columns and hold back
twigs and leaves. It's a genuine team effort.
The ants return home, carrying their spoils deep underground where millions of developing grubs are
waiting to be fed. In ant society, no job is left undone for long. Back outside, yet another task force
throws out the remains of past victims. Driver ants kill almost everything within range of their nests and
relocate from time-to-time to find enough food. With no fixed abode, wars between colonies are rare.
if on the Internet, Press <BACK> on your browser to return to
the previous page (or go to www.stealthskater.com)
else if accessing these files from the CD in a MS-Word session, simply <CLOSE> this
file's window-session; the previous window-session should still remain 'active'