Perceptual narrowing--a phenomenon in which perception is broad from birth, but narrows as a function of experience--has previously been tested with primate faces. In the first 6 months of life, infants can discriminate among individual human and monkey faces. Though the ability to discriminate monkey faces is lost after about 9 months, infants retain human face discrimination, presumably because of their experience with human faces. The current study demonstrates that 4- to 6-month-old infants are able to discriminate nonprimate faces as well. In a visual paired comparison test, 4- to 6-month-old infants (n = 26) looked significantly longer at novel sheep ("Ovis aries") faces, compared to a familiar sheep face (p = 0.017), while 9- to 11-month-olds (n = 26) showed no visual preference, and adults (n = 27) had a familiarity preference (p less than 0.001). Infants' face recognition systems are broadly tuned at birth--not just for primate faces, but for nonprimate faces as well--allowing infants to become specialists in recognizing the types of faces encountered in their first year of life. (Contains 2 figures.)