Fatherhood increases attraction to sensory stimuli from unrelated pups in male California mice, Peromyscus californicus

When becoming parents, female mammals undergo extensive physiological and behavioural changes that facilitate the onset of parental care. These include increased attraction to sensory stimuli from neonates, mediated by hormonal and neural shifts accompanying pregnancy and parturition. In some biparental species, new fathers also become more attracted to neonates; however, the underlying mechanisms are not clear. We examined the effects of becoming a father on males' behavioural responses to two sensory stimuli from unrelated pups -odour and vocalizations -in the biparental California mouse. First-time fathers and age-matched virgin males were exposed for 10 min to a pup-related stimulus (pup odour, pup vocalizations or both) and, simultaneously, to a control stimulus (unscented cotton and white noise) in a 1 x 1 m open-field arena. Fathers spent significantly more time in proximity to and in contact with pup-related stimuli, regardless of sensory modality, than control stimuli, while virgins showed no differences in their responses to pup-related and control stimuli. Neither fathers nor virgins responded differentially to pup odours, pup vocalizations or the combination of these stimuli; however, males exposed simultaneously to pup odours and vocalizations spent less time near the arena walls compared to males in all other stimulus conditions and spent more time in the empty corners of the arena compared to males presented with only pup odour. These results suggest that fathers are attracted to pup stimuli but do not show differential attraction to specific sensory modalities. Virgin males, in contrast, do not demonstrate either attraction or aversion to these stimuli. Our findings will help to elucidate the mechanisms underlying the onset of parental behaviour in new fathers, with particular emphasis on sensory plasticity.(c) 2023 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Automated summary

When becoming parents, female mammals undergo changes that facilitate parental care. In biparental species like the California mouse, new fathers also become more attracted to neonates but the mechanisms are not clear. This study found that fathers spent more time in proximity to and in contact with pup-related stimuli compared to control stimuli, regardless of the sensory modality. Virgin males, on the other hand, did not show any differential responses to pup-related stimuli.