dad

(Image: A hungry assassin bug father munches on one of his babies. James Gilbert)

Each father’s day we celebrate male parental care. But this year – perhaps while getting the old man an appreciative gift -– maybe have a think about why men want to care for their children at all. As opposed to, say, eating them alive.

Fatherhood comes so naturally to us that we can easily forget to ask about how and why it might have evolved. In fact, most fathers in the animal kingdom don’t do it. We fall into a rather rare group of species where males provide any care at all.

In our primate relatives, for instance, males are not at all doting – with a few exceptions, like male marmosets, who carry babies on their backs. This lightens the load on the female – presumably allowing her to make the male’s babies bigger, or to have more of them.

Absence makes the heart grow fonder?

Among mammals, dads rarely contribute to offspring beyond a single sperm – the mother generally nurses offspring alone. Except in Dayak fruit bats, where males have been found lactating (although still contentious).

Male and female grey jays feeding chicks. Dan Strickland/Wikipedia

It is in birds that male-female cooperation is most common, probably because feeding chicks and keeping them safe and warm is a two-person job. But in other birds – where newborn chicks can get up and walk for themselves, like chickens and ducks – the male is typically nowhere to be seen. He’s off soliciting new mates.

Best of a bad job

Males will sometimes help females out if they are unlikely to find another mate. Burying beetles breed on fresh mouse carcasses, which are very scarce. Having finally found a carcass, a male will stick around and help the female care because he is unlikely to find another – but he will also keep signalling to attract other females. The resident female is understandably not on board with this, and knocks him over while he’s trying to signal.

In many familiar species like gorillas and lions, males that appear to be caring are really mostly concerned about guarding their baby-mamas from rival males; the offspring are kept safe as a byproduct.

Ranitomeya poison frogs cooperate to raise offspring. Nicop69/Wikipedia

Yet some amazing examples of biparental care exist. In Peruvian poison frogs, the male carefully carries his tadpoles to a water pool. There, he monitors their progress for months: every week or so the watchful male calls to the female, who comes and deposits special nutritional eggs into the pool for the tadpoles to eat.

But in most cases, fathers are conspicuous by their absence – deserting the female as soon as they can.

Why so callous? To begin with, super-cheap sperm means the most successful males can potentially have unlimited offspring – if the species’ ecology allows it. This can even hold true for humans. The Sultan Moulay Ismail of Morocco, for example, may have had more than 1,000 children (compare that to the women’s record, a nevertheless astonishing 69).

But because it takes two to create a baby, the fact that some males can be extremely successful means that others get nothing (Ismail’s citadel must have been full of childless men). Today we think of ourselves as monogamous, but there are often still more childless men than women. For those male animals that are more successful, caring interferes with a winner’s strategy of pursuing mating. So in evolutionary terms males need a very, very good reason to care for offspring, or they will always do better seeking mates.

Dads defying the odds

Yet, in some species, males do all the care, with females contributing little apart from eggs. Although fairly common in egg-laying fish, male seahorses have taken it to extremes – they have a placenta and give birth to live young. Male rheas sit for weeks on a pile of up to 80 eggs, while male brushturkeys carefully tend piles of fermenting leaves so that the heat can incubate their eggs. In weird “sea spiders”, males tend eggs in all 1,300-odd species.

Male seahorses become pregnant, nourishing and protecting their fry until birth. Kevin Bryant/Flickr

Sometimes males have no choice but to care. Some males have to “mate-guard” females against rival males, right up until egg-laying – whereupon the female can run away leaving the male holding the babies. In others, like kiwis, females produce huge offspring and exhaust themselves, leaving males little option but to care. In Neanthes worms, before caring, the male resourcefully eats the female.

Occasionally, as in jacanas, males greatly outnumber females, who can therefore get away with dumping males with offspring. These males are unlikely to secure another mate, so their best option is to care.

But many of these “superdads” do some pretty cold calculus. Single dads are most likely to evolve where they still can mate while caring, and where care is cheap (like standing guard as opposed to feeding young). In territorial species like rheas and egg-laying fish, males with good territories guard clutches from many females. Or they make sure to seal the deal on their paternity. A male giant water bug carries only one female’s eggs on his back – but he makes the female mate several times while laying eggs.

In assassin bugs, males also accumulate eggs from many females, like rheas. But care is hungry work for these predators. They have a dark solution: to maintain body weight, they eat some of their own eggs.

Male scissortail sergeants eat their whole brood if it’s not big enough to bother caring for. Patrick Randall/Flickr

Male scissortail sergeant fish make an even more straightforward calculation. If the brood is too small, they cannibalise the entire brood and search for another mate. Makes sense – without a parent, the babies are doomed, so why waste them?

Humans: the verdict

Where do human fathers fit? They don’t habitually eat offspring, nor do they accumulate piles of babies from many women. As always, there is a lot of variation. Some are not involved, like the male chimpanzees to whom we are most closely related. But many enjoy a long and satisfying fatherhood, both teaching and learning from their children. These men may be more like wolf fathers – who provide food for their partner while she is pregnant and for their cubs once weaned; they also critically provide behavioural input in terms of play, and act as a role model. Most likely, this has evolved because such learning and experience are vital to offspring success in both species.

Grey wolf fathers are highly involved in parental care. Taral Jansen/Wikipedia

As a new dad myself, this father’s day, I am thankful I belong to a species where fathers can make a valuable contribution to their offspring’s lives beyond mere genetics.

James Gilbert, Lecturer in Zoology, University of Hull

This article was originally published on The Conversation.

by Keith Payne, University of North Carolina – Chapel Hill

I am one of those men for whom it is impossible to find Father’s Day gifts.

I don’t wear ties. My socks are all the same, in the interest of efficiency. I enjoy cooking, which would seem to open up some possibilities. But I have an annoying habit of buying useful gadgets as I need them, leaving my relatives to purchase paper bags specially designed for storing cheese, say, or devices that carve vegetables into the shape of noodles.

With sympathy for my family, the truth is that my favorite Father’s Day gift this year has been the gift of time. Or more precisely, a new understanding of how my perception of time is warped by the brain. I am a social psychologist who studies how people’s minds shape their subjective experiences. And there are few experiences more subjective than the experience of time.

A childhood whooshing by

Surely every parent has suffered the same pains I am feeling as my daughter turns 8.

In her first year, the sleepless nights were eternities passed under the glowing blue rectangles of an LCD clock. The days stretched out too, as I wished for the time when she could be entertained on her own by a toy or a cartoon, for even a few minutes. It felt like climbing uphill in anticipation of that time when we could coast.

Now, as she stretches from the roundness of a baby toward the long gazelle lines of a pre-teen, I feel that we have somehow accelerated too fast. Somewhere, we crested the top, but there was no coasting, only a whooshing that I can’t slow down.

Is this feeling of time whistling past inevitable? Scientists have uncovered startling insights about how the brain registers the passage of time. Understanding them won’t make that whooshing feeling go away, exactly, but it can make it less painful.

Time flies when your brain perceives it to.

The passage of time

This feeling of time speeding up or slowing down happens in a lot of areas of life.

We generally feel that our moments become more fleeting as we get older. Remember how long summer vacation seemed as a kid? And, ironically, as we get older larger chunks of time like decades seem to fly faster than smaller chunks like days or minutes.

Unpublished research by Heidi Vuletich in my lab finds that scarce resources make the future feel further away, which helps explain why poor children make more impatient decisions than middle-class kids. Time also seems to slow down during an emotionally intense event, whether it’s a car crash or a sleepless night.

Does time really go into slow motion during a car crash? Does it really speed up as we age? What these phenomena have in common is that they are all experienced retrospectively or prospectively, not in real time. There is no way to re-experience the car crash without traveling through the doorway of memory. So when we experience time speeding up or slowing down, is that happening in real time? Or is it a memory illusion?

Neuroscientist David Eagleman and his colleagues ran an ingenious experiment to find out. They used a sky-diving tower at an amusement park in Dallas. Subjects ascended in an elevator to the top of a 100-foot tower and then let themselves free fall into a net at the bottom.

Strapped to their wrists was a chronometer – a device for measuring time perception. It was a screen on which numbers flickered back and forth very quickly – so quickly that it’s difficult to identify the numbers. The point of the chronometer is that if time really slows down for the brain when falling, then a person in free fall should be able to accurately perceive more flickering numbers per second, relative to when they’re safe on the ground.

So what happened? When asked afterward to estimate how long they were falling, subjects overestimated the time they were in the air by more than a third. In their memories, time had indeed slowed down. But, according to the numbers participants reported seeing on the chronometer, time passed at the same ordinary rate as it did before the free fall.

This is why even though we seem to experience a car crash in slow motion, the extra time does not allow us any extra ability to steer out of the way. That’s because the slow motion is in our memories, not in the moment. Think of what this means for our experiences of time slowing down and speeding up: That whooshing feeling is not in our present, but only in our memories of it.

Even a child’s “firsts” can become a memory distorted by time.

The present is now

So are we doomed to feel that our children’s youth is speeding away?

It is likely to feel that way whenever we reminisce about the past. The more important lesson, though, is not about the past but the present. Now that I’m free falling toward her adolescence, it’s important to understand that time is not really whistling away from me. Each moment lasts the same as it did when she was a baby. Each moment holds as much joy and as much pain now as it will tomorrow.

And so, this insight is a call to let the remembered past and the fretted future go and to return attention relentlessly to the present. Someday I will look back, my head swimming, and remember today like those long, lazy summer days. But right now, a moment is just a moment. Right now she still loves to lay beside me and hear me read to her. Right now I am the big one and the strong one who can scoop her up in one arm when she needs it.

Right now, I am not “my dad,” I am daddy. What more could a father want?

Keith Payne, Professor of Psychology and Neuroscience, University of North Carolina – Chapel Hill