Having children is costly for all animals, not just humans.

Some media claim that young people no longer want to have children. The problem is that these media outlets may not have bothered to ask young people for their opinions. If they did, they would know that the problem is not that they don’t want to, but that they can’t. And that’s what having children is very expensive. Diapers, crib, stroller, daycare if necessary… No scientific research is needed to prove this. But what some researchers from Monash University is to demonstrate that other animals also find it very valuable. reproduction.

But since logically we will never see an iguana or a deer get a visa or pay cash, we will talk about the cost of having children in the form of energy costs. This has been calculated many times. The problem, according to the authors of a study just published in The scienceThis indirect energy costs.

There are two types of energy costs in reproduction. On the one hand, there are direct generation of this new life. They are mainly taken over by the woman, since it is this energy that is directed towards matters such as ovulation or, after pregnancy, the development of the embryo until it becomes a child ready for birth. For men, they also bear certain direct costs, such as sperm production. But there are also indirect costs, which include the energy invested in tasks beyond the sum of a sperm and an egg equal to the zygote that becomes an embryo. This includes breastfeeding babies or keeping them warm when they are cold, as well as many other factors.

These costs were considered insignificant in previous studies, But this study shows that they actually account for a very large percentage of the total costs of having children.

Having children is expensive for everyone

In the past, the energetic calculation of animal reproduction has been greatly underestimated. However, in recent years, scientists have emerged who have conducted much more comprehensive monitoring of the energy consumed during reproduction in mammals, reptiles and fish. The authors of the just published study collected data from 81 of these species and they have proven that having children is much more expensive in terms of energy than previously thought.

Research has focused primarily on females, as they soon appear to shoulder the largest energetic costs of reproduction. They are not only those that hold the embryo inside for a certain time, providing it with nutrition and protection. They are also the ones who after birth, are responsible for breastfeeding and issues such as protection, warmth and training. Not all species do the latter, but there are some that teach their young to function in their environment before leaving them to their own devices.

All these are indirect energy costs, which are very high in many species. In fact, one of the species analyzed was humans, and they were found to have very high indirect energy costs. Specifically, 96% energy there are indirect costs associated with what is consumed during the birthing process. But humans were not the species with the highest numbers. Of the 81 species analyzed, the species had the highest indirect damage. White-tailed deerwhose females invest 470 megajoules indirectly in reproduction. To give us an idea, a 100-pound person expends just over 1 megajoule in a 30-minute run.

The study authors believe that other mammals, such as elephant or whaletheir numbers must be even higher, but their metabolism is harder to track.

What about egg-laying species?

Species that lay eggs have higher direct energy costs compared to species that do not. At the end of the day, egg formation These are still direct costs. Moreover, once the babies are born, they do not pay as much attention to them as mammals.

Despite this, it was clear that on average cold-blooded animals They invested 31% of childbirth energy indirectly.

Birds were not analyzed because data on their metabolism is difficult to obtain, so we focused only on egg-laying reptiles.

Does no one think about men?

We have already seen that the indirect costs of having children were analyzed primarily in women. However, men also consume a lot of energy in matters such as courtship or fights with other males. This is much more difficult to measure, so for now research has focused on women.

Either way, the study’s authors believe that if one sex were at a severe disadvantage, evolution would tend to produce more of those who don’t expend as much energy. Therefore, the scale is most likely well balanced. You just need to study what are the problems with having children Men find them expensive.

They don’t have to remember the name of their child’s teacher or what vaccines they received. They have an advantage there. Some men have much more problems in this regard.