Elicited and spontaneous vocalizations of wild canids in southeastern Texas and southwestern Louisiana were studied from December 1972 through April 1975. Sonagrams and tape recordings of adult red wolf sounds were used to describe flat howls, barking howls, combination howls, yip howls, whimpers, growls, barks, and choruses. The flat howl of red wolves and coyotes was compared because this was the most useful sound for field recognition of unknown canids. On the average, red wolf flat howls were of longer duration and lower Hertz or cycles/second (Hz) than coyote flat howls. There were also differences in beginning, ending, and manner of Hz change of the howl of red wolves and coyotes, but these differences were not absolute.