First record of an adult female ring-tailed lemur (Lemur catta) making a male-specific howl vocalization.

Vocal communication is a critical aspect of social life in group living species. Ring-tailed lemurs (Lemur catta) are one of the most studied lemur species, yet the quantity of male specific vocalizations remains unclear. Howling has previously been described as a male only vocalization. While investigating Duke Lemur Center (DLC: Durham, N.C.) ring-tailed lemurs' responses to novel objects when separated from their group for five minutes, video and audio opportunistically captured a female howling. We sought to determine whether these vocalizations were acoustically similar to male howling or represented a different vocalization. We focused on body posture and acoustic structure of the call by analyzing spectrograms of the female's calls, and compared these features to male howls. Body posture comparison revealed similarities in the female's position and orientation of the body to males when howling. From the spectrograms, we compared the fundamental, maximum, maximum harmonic, dominant, supradominant frequencies, interharmonic intervals, and number of harmonics to values extracted from the published literature. A linear discriminant function analysis (DFA) failed to distinguish the female's calls from male howls. This is the first recording and analysis of female howling vocalizations. While male ring-tailed lemurs are known to howl to advertise their location, it's possible that female lemurs may howl for different reasons. Females may howl during high stress events, and we suggest future research to understand the conditions that elicit howling vocalizations in females in the wild and in captivity.