The Steiner Tree Problem (STP) in graphs is a well-known NP-hard problem. It has regained attention due to the introduction of new telecommunication technologies, since it is the mathematical structure behind multi-cast communications. The goal of this paper is to design an ant algorithm (called ANT-STP) for the STP in graphs which is better than TM, which is a greedy constructive method for the STP proposed in [34]. We derive ANT-STP from TM as follows: each ant is a constructive heuristic close to TM, but the population of ants can collaborate by exchanging information by the use of the trail systems. Inm addition, the decision rule used by each individual ant is different from the decision rule used in TM. We compare TM and ANT-STP on a set of benchmark problems of the OR-Library.