Peg3 conditional knockout mothers: nest-building behavior.

(a) Representative conditional knockout dams and wild-type littermates highlight differences observed in the nest-building behavior. (b) A graph shows the number of dams marked as good, mediocre and bad at building nests for their litters. “Good” dams are those who tore 100% of bedding material by 14 hours. “Mediocre” dams were able to use some, but not all of the bedding material by 14 hours. “Bad” dams are those that display no interest in tearing up the bedding material to insulate their pups.