Paternal hamsters mechanically assist the delivery, consume amniotic fluidand placenta, remove fetal membranes, and provide parental care during thebirth process

We report the first description of a male mammal behaviorally participating in the birth of his young. Djungarian hamsters, Phodopus campbelli, are na turally 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 oppor tunities to interact with pups and neither contribute to pup survival and g rowth nor provide extensive paternal care under laboratory conditions. Male P. campbelli undergo a series of hormonal changes prior to the birth of th eir first litter which are not shared with P. sungorus mates and may "prime " males to express paternal behavior. We hypothesized that P. campbelli mal es would behave paternally on first contact with pups during the birth proc ess, whereas P. sungorus males would not. In addition to showing paternal b ehavior toward neonates, male P. campbelli licked amniotic fluid before the birth, mechanically assisted the delivery, opened an airway by clearing th e 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. (C) 2000 Academ ic Press.