In Island Troll Tribes there is a trade system involving an elaborate placement of river trade routes. Trade ships will move through these routes around the central rivers of the map, allowing trolls to sell and purchase items.

Animal Hides and Hawk Eggs are very profitable when you sell them to ships, and ships provide a multitude of items which you can buy in exchange. Some of the ships sell whole buildings, a bargain for any troll tribe willing to take advantage of it.