Paternal urine elicits increased maternal care in grasshopper mice

Southern grasshopper mice, Onychomys torridus , exhibit monogamous pair bonding. Both mother and father display high levels of parental care of their offspring. Based upon earlier work (Schultz, N. J. (1979) . Paternal role and behavior of the southern grasshopper mouse, Onychomys torridus . Doctoral thesis, The Johns Hopkins University), if the male of a pair is removed from the female and their litter, maternal pup licking, an important parental care action, declines. However, if isolated mothers with pups are exposed to urine samples collected from their respective mates, maternal pup licking increases significantly. The effect does not appear for a few days, but then increases rapidly and significantly. Apparently, paternal urine contains a chemical cue that increases levels of adaptive maternal care toward young.