Distinctive heart-shaped abdomen when viewed from above. 1/8- to 1/4-inch; black, dark brown, or red and black. Like carpenter ants, acrobat ants prefer to nest in moist or rotted wood. Colonies are most often found in tree holes, dead limbs and rotting areas in fences, decks and railings. Indoors, nests may be located where water damage has occurred, in decayed or damp wood or inside insulation wall panels and wall voids. When disturbed, acrobat worker ants run with their abdomens held high over their heads.