Beyond maternal care: The effects of extra-maternal influences within the maternal environment on offspring neurodevelopment and later-life behavior

•Maternal care has a profound effect on later-life behavior in offspring.•Extra-maternal factors have also been shown to influence later-life behavior.•We discuss variations in ambient temperature exposure and gene x environment interactions.•Other examples include milk composition, sibling interactions, and paternal care.•Future work on extra-maternal influences is important to understand the development of behavior.