The power of an image may be demonstrated in these verses. There are few readers of the Book of Mormon who have seen the Frieberg painting depicting Ammon with a metal sword guarding a herd of sheep who can help but see these "flocks" as sheep. In fact, the text never tells us what kind of animals these flocks are (the use of the terms flocks and herds in the Book of Mormon are problematic, see the explanation following 2 Nephi 5:11). We know only two things, that they require water and that they may be easily scattered. This latter behavior rather discourages the image of sheep, as they will tend to stick together rather than scatter. Whatever animal it was, it was not one with a herd instinct, and was one that was fast enough that when scattered they could not be easily recovered.
This entire episode requires some careful examination. Ammon intends that we read it as a story of the power of the Lord, and so we do. However, we should also read it for what it tells of us Lamanite society, for there are parts of the story that otherwise seem to make little sense.
First, we must set the basic scene. There is a place of water that appears to be required for whatever animal was in these flocks. This place of water is clearly in territory pertaining to King Lamoni, as it is inconceivable that there would be a major trail drive simply to take animals to water, particularly since this was a regular function. Into this area we now have a continuing set of marauders. We find in chapter 18 that these are thieves:
Alma 18:7
7 Now it was the practice of these Lamanites to stand by the waters of Sebus to scatter the flocks of the people, that thereby they might drive away many that were scattered unto their own land, it being a practice of plunder among them.
The attackers as well as the attacked are both Lamanites. Thus we are not seeing a Nephite/Lamanite conflict, but a Lamanite/Lamanite conflict. This is an important aspect of our understanding of the Book of Mormon because it is rather common to see the Lamanites as a homogeneous population. There are clearly divisions among the Lamanites that are not only indicated by multiple kings, as we will see during the story of the sons of Mosiah, but also differing factions. These thieves may or may not have had the approval of their own city, but it is rather unlikely that they would be connected to the city where Lamoni resided, because they might be recognized. Their anonymity is assured only if they are from a different city.