Another category of interactions between organisms has to do with close, usually long-term interaction between different types of organisms. These interactions are called symbiosis
I believe it is competition. Animals of the same species have to compete for resources, mates, shelter, and space to survive. Symbiosis, like the other commenter said, is an interaction between organisms, but it helps both organisms. If they are both looking for the same thing (ie food) it is not symbiosis.