What is “being a good father,” biologically speaking?

From this perspective, it would be the one that seeks the survival of its offspring, at least until it acquires sexual maturity.

Thus, all parental behavior that increases the possibilities of reproduction of children would be considered an adaptive character, would increase the biological efficacy of the species and, consequently, would be favored by natural selection.

Parental care, therefore, are advantageous. However, and strange as it may seem, they are also extraordinarily scarce. Because?

The first reason would be related to our habit of discerning if the neonatal creature looks more like Mom or dad.

From the entrance, in most species (which have larval phases), the discussion would be irrelevant, because “the creature” does not look remotely, remotely, any parent.

Its appearance is radical and surprisingly different. So much so that, when biological knowledge was more limited, different vital phases of many species have often been considered not only different species, but radically different groups.

In fact, these divergences between parents and children are not only anatomical and physiological, but also ecological.

That means that descendants, in their early vital phases, do not share habitats with their parents and live in different “universes”.

Let's put an example known to all: mosquitoes. Their larvae are “worms” that live, eat, breathe and develop in the water, while their parents live in “another galaxy”: the aerial medium.

In these circumstances, interaction is practically nil, coexistence does not exist and parental care is not feasible.

By contrast, we might think that, when there are no larvae, parents will be interested in the fate of their creatures presupposing that we take care of “what we find.”

Well, let's discard our beautiful and tender hypothesis: in most species, parents disregard their progeny once they have hatched the eggs.

There are several factors that seem to be involved, and to understand them you have to take into account, first, obvious: to take care of the offspring you have to be alive.

From this perspective, they could not “be good parents all those to whom the reproductive effort assumes death.

Even if they wanted, the salmon could not take care of their children because, after tracing the river where they were born, they die when it was spawning.

Another element to consider would be the number of descendants generated in a reproductive process.

It is evident that it is difficult to prepare breakfast at the 20,000 children you just have from a cup (when, in addition, they are confused with the 20,000 of each of your neighbors, as could happen in many marine species with external fertilization).

Thus we eliminate the possibility of parental care in all species that bet more about the amount when achieving the survival of any of their descendants than for the quality of the care that are granted to a small number of offspring.

A third essential factor to take care of children is the possibility of having a safe place where children can survive while parents seek food.

The existence of this “nest-hogar” is a characteristic that share mammals and birds with social insects such as bees or ants.

It also influences the hardness of the physical environment in which the offspring develops, making parental care to achieve their survival.

Thus, the females of the arachnid telifónido mastigoproctus giganteus transport the small preninfas in an abdominal incubator chamber, guaranteeing the essential humidity to survive in extreme aridity environments.

Even more curious is how, in the case of some predatory species, their own nature.

A very striking example is that of many great shades, which present the calls nursery grounds.

These areas are, basically, submarines “nurseries” where the fierce “tiburon mothers” orbit swimming around their young and avoiding the attack of the males of their species.

But perhaps what determines the existence of parental care is the level of altricity of children, that is, their degree of helplessness for not having the ability to feed and subsist for themselves.

Here we include all mammal species (which depend during their first phase of breastfeeding), but also to most of the birds that need care after birth before being able to develop autonomously.

If we join all the requirements, the care has been mainly developed in species that do not die when they reproduce, which have direct development (without larvae), which have few descendants per reproductive event, which do not contemplate their own offspring as possible foods and, what is more important, whose young need their parents for their own survival.

In that reduced group of species, social insects, modern birds and mammals eutremas would be fundamentally.

The vertebrates offer us a broad sample of possibilities in the care of the children and there seems to be a certain prevalence of each modality of care in the evolutionary lineages of each group.

In the few bone fish that deal with the young, males frequently do it. In the well -known example of the hippocampus, it is the seahorse “dad” the one who transports to the offspring until the youth can swim freely.

Here the female is limited to putting fertilized eggs in her partner's ventral bag, which is the one who looks “pregnant.”

Cyclide males, on the other hand, secrete a kind of milk-milk through the skin from which the young feed, although this task shared with mothers.

However, the best known case of parents involved in the care of the offspring is that of birds, where the care is biparental.

This behavior is a consequence of the homeotherm development of their embryos, that is, the eggs must be split so that they are warm. If they cool, embryonic development abort.

In this absorbent and continuous activity natural selection has allowed the relief and favored social monogamy. In 95 % of the birds, couples are maintained during the breeding season and both parents are pulled by eggs.

In the case of mammals, “parental” care is clear and massively “maternal.”

Mammals are lucky that our embryos are not predated, trampled, carried by the current or a thousand more circumstances that affect oviparous species.

On the contrary, we place our embryonic and fetal development within a warm, safe and maternal uterus. This mother-child bond continues during breastfeeding (which also is in charge of females).

All this is a huge increase in the survival rate of the young. In the case of primates (and especially in that of humans), in addition, the potentialities of the species multiply with the possibilities of spending a lot of time to “teach”, developing a double heritage (genetics and cultural) that has no paragon in the living world.

This fact deserves an interesting reflection: the great advantage that for mammals that viviparity has meant, females almost exclusively pay (in our case, women).

The “good human father”, since it cannot be biologically, has the fascinating possibility of doing so culturally and compensating this unfair balance based on love, time and teaching to their children.

Fortunately, more and more are those who discover this unpayable privilege.

* A. Victoria of Andrés Fernández is a titular professor in the Department of Animal Biology, University of Malaga. This article appeared in The Conversation. You can read the original version here.

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