Table 1. Ethogram used for the assessment of maternal care behavior in C57BL/6N and Balb/c dams.

	Description	Categorization
In nest
licking/grooming	dam touches the pup's body with her tongue, dam handles the pup's body with her forepaws or nose	caring behavior
active nursing	dam presents an upright dorsal arch posture with the depressed head posture over the pups which are attached to the nipples	caring behavior
passive nursing	dam lies immobile on pups and has her eyes open or closed	caring behavior
nest building	dam collects and/or handles nesting material around the pups with mouth or forepaws	caring behavior
self-grooming	licking, brushing or scratching fur or paws with tongue or paws inside the nest	self-maintenance
pups out of nest	pups are outside of the nest with no contact to dam, to other pups or nesting material	neglecting behavior
Out of nest
eating/drinking	chewing food, sawdust or feces; licking water from bottle tip	self-maintenance
self-grooming	licking, brushing or scratching fur or paws with tongue or paws outside the nest	self-maintenance
climbing/digging	dam climbs with all four paws attached to the cage lid, dam uses forepaws to scratch sawdust away from her body	neglecting behavior

Behavioral measures are categorized according to their presumed function in ‘self-maintenance’, ‘caring’ and ‘neglecting behavior’.