When we take into the consideration that an ant's brain has gray matter analogous to the gray matter found in the cortex of the human brain, we should not feel surprised when we find striking evidences of ratiocination in these little creatures. The better creatures are able to communicate ideation or thought, the stronger and more frequent are the evidences of their possession of reason. Ants can undoubtedly communicate; how and in what manner, it is not generally agreed.
Some time ago I crushed an ant in a path usually taken by the inhabitants of a nest (which was situated in a hollow tree) in their journeys to and fro. A soldier ant came along presently, and, smelling the blood[78] of her murdered companion, was seized by a sudden terror and fled away into the nest. She soon returned, however, with thirteen other soldier ants, and made a careful examination of the body and its surroundings. Her companions also examined the corpse, and, having satisfied themselves that their comrade was dead, and that her murderer was not to be found, returned to the nest. Soon afterwards a large worker ant, guarded by two soldier ants, came out, and, proceeding to the body, picked it up, carried it down the tree and away beneath the grass, where I lost sight of them.
In this instance there is every evidence of complex reasoning; the discoverer of the murder hurried away into the nest, where she gave the alarm; the police of the community—the soldier ants—went immediately to the scene of the tragedy, made an examination, and then returned and gave in their report; the undertaker, in the shape of the large worker ant, then went out, got the body, carried it away and buried it; the two soldier ants followed the body to the grave in order to protect it from cannibal ants.
It has been my good fortune to have witnessed several pitched battles between large bodies of ants. In a battle between some black ants and some yellow antagonists of another species, I saw many evidences of intelligent communication. The yellow ants had a commissariat and an ambulance corps; and I frequently saw them drop to the rear during the battle, and partake of refreshments or have their wounds attended to. The blacks, which composed the attacking army, were in light marching order, and had neither of these conveniences and necessary adjuncts. The yellow ants frequently sent back to their village for reënforcements; the ants that had been out on hunting expeditions when the battle was joined were notified as soon as they arrived at the nest, and immediately hurried off to join in the fray. The blacks had discovered a herd of aphides belonging to the yellows, and had sought to surprise the guards and steal the herd; hence the battle. I am glad to report that the black horde was defeated by the brave yellow warriors and had to decamp, leaving many of its number dead upon the field of battle.
On another occasion I saw an army of red ants besieging a colony of small black ants. The object of the red ants was the theft of the pupæ or young of the black ants. These pupæ they take to their own nest and rear as slaves, the enslaved ants to all appearances becoming entirely satisfied with their condition, and working for their masters willingly and without demur. The besieged ants evinced a high degree of reason and forethought, for, as soon as the presence of the besiegers was noticed, strong guards were posted in all of the approaches to the nest, both front and rear. The red ants sent a detachment to surprise the colony from the rear; but they found that surprise was impossible, for they were met by a strong party of their gallant foes which vigorously opposed them. The red ants were, however, eventually victorious, and sacked the town, carrying away with them a large number of pupæ.
I cheerfully bear witness to the fact that the great myrmecologist, Huber, was correct in his description of his experiment with the black slave.[79]
Like Huber, I put some of these red slave-owners into a glass jar in which I placed an abundance of food. Notwithstanding the fact that this food was easy of access, being in fact immediately beneath their jaws, they would not touch it! I then placed a black slave in the jar; she at once went to her masters, and, after thoroughly cleansing them with her tongue, gave them food. These red ants would have starved to death in the midst of plenty, if they had been left to themselves.
This, at first glance, would seem to indicate an utter absence of reason in these red slave-owners. Such a conclusion, however, is by no means true. The facts indicate mental degeneration. So utterly subservient had they become to the ministration of the slaves, that they had even lost the faculty of feeding themselves!
Here, we have an example of degeneration in the mentality of an animal incident to the enervating influence of slavery. Sir John Lubbock's remarks anent the four genera of slave-making ants are so interesting that I may be pardoned for quoting them entire. Says he:—
"These four genera" (Formica sanguinea, Polyergus, Strongylognathus, and Anergates) "offer us every gradation from lawless violence to contemptible parasitism.