The first 3 are the older or sick and they set the pace of the group.
If it was on the contrary, they would be left behind and lost contact with the pack.
In ambush case they would be sacrificed.
The following are the 5 strongest.
In the center
follow the remaining members of the pack.
At the end of the group the other 5 stronger.
Last, alone, follows the alpha wolf.
It controls everything from the rear.
That position can control the whole group, decide the direction to follow an anticipate the attacks of opponents