Besides these, there are Indians of another tribe, who border on the city of Caspatyrus, and the country of Pactyïca; these people dwell northward of all the rest of the Indians, and follow nearly the same mode of life as the Bactrians. They are more warlike than any of the other tribes, and from them the men are sent forth who go to procure the gold. For it is in this part of India that the sandy desert lies. Here, in this desert, there live amid the sand great ants, in size somewhat less than dogs, but bigger than foxes. The Persian king has a number of them, which have been caught by the hunters in the land whereof we are speaking. Those ants make their dwellings under ground, and like the Greek ants, which they very much resemble in shape, throw up sandheaps as they burrow. Now the sand which they throw up is full of gold. The Indians, when they go into the desert to collect this sand, take three camels and harness them together, a female in the middle and a male on either side, in a leading-rein. The rider sits on the female, and they are particular to choose for the purpose one that has just dropped her young; for their female camels can run as fast as horses, while they bear burthens very much better. As the Greeks are well acquainted with the shape of the camel, I shall not trouble to describe it; but I shall mention what seems to have escaped their notice. The camel has in its hind legs four thigh-bones and four knee-joints.

[...]

When the Indians reach the place where the gold is, they fill their bags with the sand, and ride away at their best speed: the ants, however, scenting them, as the Persians say, rush forth in pursuit. Now these animals are, they declare, so swift, that there is nothing in the world like them: if it were not, therefore, that the Indians get a start while the ants are mustering, not a single gold-gatherer would escape. During the flight the male camels, which are not so fleet as the females, grow tired, and begin to drag, first one, and then the other; but the females recollect the young which they have left behind, and never give way or flag. Such, according to the Persians, is the manner in which the Indians get the greatest part of their gold; some is dug out of the earth, but of this the supply is more scanty.

—Herodotus, History, III, 102-105