Paternal hamsters mechanically assist the delivery, consume amniotic fluid and placenta, remove fetal membranes, and provide parental care during the birth process.

We report the first description of a male mammal behaviorally participating in the birth of his young. Djungarian hamsters, Phodopus campbelli, are naturally biparental and males contribute to pup survival and growth through direct paternal care and indirect effects on maternal physiology. Males of the closely related Siberian hamster, P. sungorus, have only seasonal opportunities to interact with pups and neither contribute to pup survival and growth nor provide extensive paternal care under laboratory conditions. Male P. campbelli undergo a series of hormonal changes prior to the birth of their first litter which are not shared with P. sungorus males and may "prime" males to express paternal behavior. We hypothesized that P. campbelli males would behave paternally on first contact with pups during the birth process, whereas P. sungorus males would not. In addition to showing paternal behavior toward neonates, male P. campbelli licked amniotic fluid before the birth, mechanically assisted the delivery, opened an airway by clearing the nostrils (so that pups flushed red with oxygenation), licked and sniffed pups in the moments and minutes after birth to clean the pups of membranes, and ate the placenta. None of these behaviors were observed in P. sungorus. We anticipate that P. campbelli will not be the only species with highly developed paternal behavioral repertoires during the birth. Copyright 2000 Academic Press.