Researchers attempt to explain the persistence of altruism by the theory of Self-sacrificing behavior
Step-by-step explanation:
The altruism behavior of animals is common. It can be seen specifically to the species of complex social structure. It involves a typical behavior of donating or serving to the other members of the same group of animal.
This behavior includes sacrificing and thinking about other members of the group instead of thinking about own self leading to the ignorance of their own fitness. For example- The bees work for the queen bee, nest construction and protection of the queen.