Ultrasonic communication has been reported in mice in three different social contexts: mother-infant, male-female and female-female social interaction. These signals belong to the same frequency range, around 70 kHz. While in the first two cases ultrasounds have been interpreted as infantile signals that inhibit aggression, no clear functional explanation has been suggested for female-female interaction. As ultrasounds are usually associated with intense sniffing on the part of the emitter, we tested the hypothesis that these vocalisations can be associated with information concerning food quality eaten by a conspecific. We measured the amount of ultrasonic calls emitted during the first three minutes of a female-female interaction. A preliminary analysis showed that most of the vocalisations were emitted by the resident animals. Moreover, the quality of the food eaten by the female intruder affected the amount of ultrasonic calls uttered by the resident; in fact, female fed on highly palatable familiar food elicited a greater amount of calls. This data suggests that animals are able to detect the characteristics of the food eaten by their conspecifics and show more interest is individuals fed on highly palatable food.