Forget lions, tigers, and bears. When it comes to the art of war, army ants are among the most frightening creatures on earth . With powerful mouth parts, these fighters can skillfully cut creatures much larger than themselves into pieces. Acting together in great numbers, army ant colonies succeed at making tens of thousands of such kills each day. Their capabilities do have limits, though. Contrary to popular belief, they almost never take down large animals or people.

One of the best places to observe army ants is Barro Colorado, an island in a lake created by the Panama Canal. The island is home to as many as 50 colonies of Eciton burchellii, the most studied army ant in the world. It is one of 150 types of army ants in the New World; more than 170 other types live in Asia, Africa, and Australia.

The colonies of this army ant are huge, ranging from 300,000 to 700,000 ants. They never stay in one place long, moving from nest site to nest site. Linking legs together, they use their own bodies to form enormous nests called bivouacs, which they hang beneath a fallen tree. There they stay for about 20 days as the queen lays as many as 300,000 eggs.

When the ants go hunting, as many as 200,000 of them leave the nest in a group that broadens into a fan as wide as 14 meters. This swarm raid takes a slightly different course each day, allowing the hunters to cover fresh ground each time.

Protecting the ants wherever they go a re the soldiers, recognizable by their oversized jaws. If their frightening looks don't scare enemies away, soldiers also have a powerful bite and the attack is often suicidal. Because their jaws a reshaped like fishhooks, the soldiers can't pull them out again. Amazonian tribes have used soldiers ants to close wounds, breaking off the bodies and leaving the head in place.

Eciton Burchellii are blind and can't see what's ahead of them, but they move together in such great numbers that they easily kill the non-army ants, insects, and other small creatures that constitute their prey. When the groups happen upon a break in the path, ants immediately link legs together and form living bridges so that the groups can move forwards without any delay.

In Japanese the word ant is written by linking two characters: one meaning "insect," the other meaning "loyalty:' Indeed, individual ants a re completely loyal to their fellow ants. They display many examples of selfless cooperation that, while certainly extreme, can't fail to win human admiration.


24. Which of the following statements about soldier ants is NOT true?
A. People can use them to close wounds
B. They can see nothing a head of them
C. They have powerful bites
D. They lay many eggs
E. They link their legs together to form a living bridge