Panthers are usually quiet, but under some circumstances they do communicate panther through vocalizations. Sounds they make have been described as chirps, peeps, whistles, purrs, moans, screams, growls, and hisses. When frightened, kittens emit a series of short, high-pitched peeps. Kittens and mothers keep track of each other with whistles. Females signal their readiness to mate by yowling or caterwauling.