This post explores the theme of altruism in animal behavior, and the problem it raises. I will explain the interactions between animals of the same species, focusing on altruistic behavior, which comprises negative effects on the actor and positive effects on the recipient. Because Charles Darwin's theory of evolution can not explain this behavior, theories arise to solve it: group selection, kinship selection, parental care, cave theory, 'never breaking the ranks' theory and reciprocal altruism.

As has already been mentioned, between individuals of the same species there may be behaviors that are malicious, selfish, biased, and altruistic.

Malicious behavior has negative effects on both actor and receiver. Pierott (1980) and Gadagkar (1993) give the example of the gull (Larus occidentalis) that "steals" food and attacks the females of other individuals of the same species. However, males who demonstrate this behavior have fewer offspring than those who do not.

In the case of selfish behavior, the actor is benefited and the recipient is harmed. Some seagulls are an example of this, because by stealing food from neighboring nests to feed their offspring, they increase their performance to the detriment of the neighbors.

In relation to the mutual behaviors, these will be provided to the actor and to the receiver. It is the case of the wolf (Canis lupus), which makes hunting along with others in the group, increases the likelihood of prey capture towards all food.

Finally there is altruism</ b>. According to Richard Dawkins an altruistic behavior increases the hypothesis of survival of a similar entity (receiver), with prejudice of itself (actor). That is, an altruistic act, is disadvantageous for the performer.
As an example of an altruistic act, we can mention the sharing of food among chimpanzees (Pan troglodytes), or social alocatage. In the case of social allocation, it comprises two functions: the hygienic function, in which objects, dead skin and parasites are removed; and strengthens and stabilizes relationships among the individuals in the group (Boyd and Silk, 2006).

However, by harming the actor and benefiting the recipient, altruistic behavior conflicts with Darwin's Natural Selection theory.
It is based on the idea that individuals who are better adapted or with characteristics appropriate to particular environments and temporal spaces will survive and be more successful than individuals less adapted to their environment.
Therefore, they will be the ones to have greater reproductive success, either by living longer, increasing the number of offspring, or by transmitting characteristics advantageous to their offspring, which triggered the increase of their reproductive differential. Marking the species with this characteristic, without looking at the impact of the same on other individuals.
How to solve this incompatibility between the theory of evolution and the existence of altruistic behavior?

3. The problematic of altruism

Since altruism faces several facts that deny its true essence when it occurs in the natural environment, the question arises:

3.1.How did altruism survive within the evolutionary mechanism?

This can be explained by the idea of "false altruism". There are several examples that provide a better understanding of the motives that may lead individuals to perform altruistic behavior, in which their performance is apparently impaired, but under closer observation are acts that will in some way be advantageous for the actor.
There are several altruistic behaviors that can be referred to.

In the case of primates, we often observe social grooming, which plays an important role within the group as a link between community members. This behavior benefits the performers in two ways. It allows the hygienic maintenance, removing parasites and debris, and allows to strengthen social relations with the other elements of the group. A blatant example of this process occurs with baboons. They invest heavily in the maintenance of their social relations, and their communities are extremely hierarchical. However, if we look closely, resorting to this apparently altruistic behavior will benefit the actor, even if in the long run, by strengthening links and affiliations between the group, by creating an alliance, guarantees support to the competition and predators in the future. Thus, the altruistic foundation becomes null.

The same goes for the alarm vocalizations. This behavior can be highly detrimental to the actor, since often issuing alarm vocalizations means revealing his position to the predator to improve the group's chances of survival.
As mentioned in the Sherman study, which in 1985 carried out a study on the species of squirrels Citellus belding, in which it realized the experience of observing the emission of alarm vocalizations. Sherman determined that 14 of the 107 who performed vocalizations were actually attacked by the predator, and that of the 168 non-vocalists only 8 were attacked. Therefore, it is concluded that the individuals who were on watch, actually protected the rest of the group, saving a large number of elements. But once again, we can call into question the altruistic authenticity of this behavior, since these watch functions can be occupied in a random way, there being a rotation between the elements of the group, which will cause each individual to be less harmed, benefiting from protection on a more regular basis. But even if that does not happen, we can not ignore the fact that in protecting the rest of the group, it is also to protect their genetic inheritance, since generally the constituent elements of the group share degrees of kinship (case of Group Selection).

Até mesmo na partilha de alimentos, que pressupõe a transacção de alimentos de livre vontade, e geralmente ocorre entre indivíduos que partilham laços de parentesco próximos, mais usualmente entre progenitora e cria, os benefícios a longo prazo acabaram por ocorrer, pois é provável que posteriormente, seja a cria a partilhar alimento com a sua progenitora ou irmãos, dependendo das circunstâncias.
Assim, a comunidade científica identificou um paradoxo no altruísmo, o que levantou uma serie de questões que mais tarde seriam respondidas por teorias propostas para tentar explicar esta problemática.