Let’s take a moment to appreciate the father figures in our lives—and in the lives of mammals, evolutionarily speaking.
Having a huge brain (proportionate to our bodies, at least) comes with its share of hazards. For instance, we must emerge into the world with gigantic heads, and all that grey matter requires so much energy that our young aren’t capable of much more than crying and pooping. The mother of any baby primate typically does her fair share to tend to that helpless bundle of joy, of course, but it’s often just too much of an energy load for any one individual to manage on their own.
Evolutionary biologist Sandra Heldstab and colleagues Karin Isler, Judith Burkart and Carel van Schaik from the University of Zurich’s Department of Anthropology examined family parenting dynamics and brain size in 480 mammalian species. Previously, common belief held that any member of the family was equally likely to help out, but this doesn’t seem to be the case. When it comes to the large-brained mammals, fathers in particular tend to be the ones to pick up the child-rearing slack.
“Fathers help consistently and dependably with the rearing of offspring, whereas assistance from other group members, such as elder siblings, for instance, is far less reliable,” says Sandra Heldstab.
That’s right, we can partly thank the big-brained mammal dads for our own precious skull meat. Not only were, say, siblings less likely to help out, but the team’s observations found that, for instance, among wolves, a sibling was more likely to steal a carcass meant for the baby than to provide for the newborn. To a parent wolf, one’s young must be cared for, but to a brother or sister wolf, that baby is competition.
How did this play out among mammals where the father tends to be a little, well, useless? Lions, for example, birth many cubs with smaller brains, creating less of an energy suck and increasing the possibility that at least some of the young will survive despite their deadbeat dad.
Still, if you have a less-than-ideal relationship with your own dad, don’t despair. You don’t need to be a lion cub to turn out alright; the willingness to nurture young that is not one’s own direct offspring seems to be a somewhat uniquely human trait. We distinguish ourselves from even the apes by our readiness to drop everything for a crying baby who doesn’t even share our genetic material. That’s just part of why our extended families and friend networks allow us to survive.
Still, we stand on the evolutionary backs of large-brained monkey fathers. So the next time someone tries to sound macho by describing themselves as an “alpha male,” treat them like the equivalent of a wolf or ape patriarch: hand them a squalling baby in a dirty diaper and tell them to get to work.