In her book Father Time, Sarah Blaffer Hrdy explores the role males play in parental care and its evolutionary basis. Now, the book has inspired a 52-minute documentary called Father Time: Why Men Are Born to Nurture.

The book Father Time is a personal investigation into the deep history of male care, beginning with the very first caretakers, male ones among fish over 400 million years ago, through eons of mammalian and primate evolution.