Intranasal oxytocin increases social grooming and food sharing in the common vampire bat Desmodus rotundus I gave two groups of highly familiar captive vampire bats intranasal oxytocin. In the first group intranasal oxytocin led to larger regurgitated food donations. In the second group, I gave a larger dose and found that oxytocin also increased allogrooming between adult females. I did not detect effects on donation probability or number of grooming partners. The peak effect of intranasal oxytocin occurred 30-50 minutes after inhalation, matching the time that intranasal oxytocin causes a spike in brains of rats and mice. This suggests that intranasal oxytocin does not enter the brain directly. This paper also shows that oxytocin can be used as a tool in future manipulations of vampire bat cooperation.