Whether you believe in Darwin’s theory of evolution or not, it is currently the theory with the most direct evidence, but it does have some problems.
One of the biggest loopholes is why, as individuals, we behave altruistically? You know, altruism often means that you need to pay the price.
If you have to sacrifice yourself, then this is completely inconsistent with the natural selection view,Because the “evolutionary game” of natural selection must increase the chance of copying one’s own genes at the expense of other people’s genes.
Ethologists have tried for decades to understand the motivations behind altruistic behavior, with little success, and this hole in evolution has been left unplugged.
However, the strange parenting behavior of a North American squirrel may close this gap.
kind red squirrel
Squirrels have many natural enemies. During the breeding season, they often leave a litter of cubs waiting to be fed, while they themselves are preyed upon by natural enemies.
A strange species of red squirrel living in Canada’s Yukon Forest has adopted the offspring of other squirrels.
In fact, adopting cubs in the animal world is nothing new, but voluntary adoption of the same kind basically occurs in captivity, and it is very rare in a purely wild environment.
Red squirrels were initially found to often have offspring with large differences in size in their litters, which is unusual because the animal’s parenting behavior is very different from that of humans, and animals tend to rush to a favorable time when food is plentiful Duan gave birth to several cubs in one go, and then raised them together.
Therefore, in their family, all cubs should be regarding the same size.
This strange phenomenon has caught the attention of scientists, and researchers from the University of California, Berkeley have launched a study on it.
They found litters with different pups, collected DNA from those pups, and determined that the larger pups were indeed descended from other squirrels.
It’s actually weird here, too, because squirrels might adopt those older cubs, which would obviously be detrimental to their own future development.
However, further research has found that squirrels are not adopted casually, and their adoption is conditional, that is, all adopted cubs are blood related to themselves, and they will never adopt any cubs that are not related to themselves .
On the other hand, even if they meet the adoption conditions, they will measure who they adopt according to their own conditions. When they have more children, they will choose to adopt those offspring who are closer to their own blood. When there are fewer children, the requirements for blood relationship will be relatively lower.
For example, if a female squirrel already has two pups, she might adopt her niece or nephew. But when she has three cubs, she will only adopt her grandchildren or younger siblings.
According to these adoption conditions, the research team gave a guess,The adoption behavior of squirrels does not conflict with natural selection. Adopting offspring that is related to them is actually a way to pass on their genes, because these offspring have similar genes to them.
The reason why adopters are judged according to their own conditions just confirms natural selection, because this kind of selection of adopted offspring is actually how they measure how to pass on their genes more.
My grandchildren or younger brothers and sisters have significantly higher genetic similarity with me than my nieces and nephews, so when the adoption conditions are not good (more offspring are raised), it is obvious to adopt individuals with high genetic similarity with myself. may result in higher returns;
When the adoption conditions are good, they lower their requirements, which is like getting a gift in the process of raising. Even if they have less blood relationship with themselves, they can somewhat increase the return.
The decision to adopt larger or smaller cubs may be made following weighing.
How does this relate to altruistic behavior?
By only adopting orphans related to themselves, the behavior of red squirrels actually makes us think that maybe kindness or altruism may just be a selfish means to increase the genetic fitness of individuals.
Essentially, you pass on your genes by bearing children yourself or by helping relatives raise their children.
This is in line with natural selection.
In human societies, however, the act of adoption can be more altruistic, and many people do adopt children who are not related to them.
Regarding this point, the researchers of this study did not directly give an explanation, they just put forward some possible hypotheses, which can be regarded as some explanations for altruistic behavior.
(This study is from 2011, and it’s still hard to tell what’s going on with animal altruism until now.)
First of all, human ancestors lived in small clans, and the earliest adoption behaviors basically only occurred between related individuals—as long as you adopted, you were basically related to yourself by blood.
Secondly, creatures actually know how to use some “reward and punishment mechanisms” to complete the choice that is most suitable for their own survival-whether to avoid or continue to act.
For example, it is easy for us to feel happy when we are studying. Its essence may be that learning can help us survive, and happiness can allow us to continue learning.
On the other hand, we have an innate disgust and fear when we see some things, and its essence is to want us to avoid them.
Whether it is happiness or disgust, they are actually helping us survive, in other words, passing on more of our genes.
It is likely that humans “learned” the advantages of adopting other people’s offspring—which can also pass on our genes—in the survival mode of small clans, and evolution allows us to take pleasure in adopting children or other emotions that motivate us to continue to act.
Eventually, we showed complete altruistic behavior-adopting children who have no blood relationship with ourselves.
If this is the case, then this altruistic behavior of humans is actually developed from the adaptation of natural selection, but it is a bit excessive.
In fact, in the process of evolution, organisms often “exert too much force” and then show some strange behaviors, and altruistic behaviors may also be the same.
However, the altruistic behavior of other animals is much more complicated than this, and this explanation cannot represent all.
