Competitive/competition exclusion principle is when species cannot live in the same space for an extended amount of time due to the use of similar resources. When two or more species have the same diet, occupy the same habitat, use the same hiding spots, etc., one species will use the resources more efficiently thereby “competitively excluding” the other species.
Picture Source:
http://2.bp.blogspot.com/-tUMXe1mnwRs/UGvC5ZywMMI/AAAAAAAAB20/npupVPvf4Aw/s1600/dangerous%2Banimal%2Battacksnews%2BLion%2Band%2B%2BHyenas%2BFighting%2Blion%2Bfacts%2Bhyena%2Bfacts%2Banimals%2Bhunting%2Blions%2Bhunting%2Bhyena%2Bhunting%2Bin%2Bthe%2Bwild%2Bbeautiful%2Bdangerous%2Banimal%2Bpictures.jpg