Post-weaning parental care increases fitness but is not heritable in North American red squirrels.
Lane JE, McAdam AG, Charmantier A, Humphries MM, Coltman DW, Fletcher Q, Gorrell JC, Boutin S. Post-weaning parental care increases fitness but is not heritable in North American red squirrels. J Evol Biol. 2015 Jun; 28(6):1203-12.