Mai Sakai, a lecturer at the Department of Fisheries, Faculty of Agriculture, Kinki University, discovered that young females who have no experience in raising children can be seen raising unrelated children as foster parents in wild dolphins.It was the first time in the world that foster parent behavior was confirmed in whales to which dolphins belong, and it was published in the electronic version of the British life science magazine "Scientific Reports".
About 120 wild bottlenose dolphins live around Mikurajima in the Izu Islands, and individual identification surveys have been conducted by the Mikurajima Tourism Association for over 20 years.The research group of Kinki University has continued to investigate and observe in cooperation with the association.In this survey, Sakai and his colleagues discovered that a child whose mother died shortly after birth was swimming with a young female who had never been raised.Upon closer examination, the female was not only breastfeeding, but also swimming with her and stroking her breasts.This foster parent behavior lasted 102 days.
When the DNAs of the actual mother and the foster female were collected and collated, there was no blood relationship, and there was no "affinity social relationship" such as swimming side by side.The research group suspects that a young female with no child-rearing experience happened to be near her baby when she had an accident.
The behavior of caring for unrelated children has been seen in some animals, such as primates, but not in cetaceans.It is thought that the dolphin's characteristic of "helping others" may have led to this case, and in the future it will be clarified whether that characteristic has influenced foster parent behavior.It has been noted that research on the behavior of dolphins living in a complex society like humans can be a hint to unravel the roots of "helping each other" in human society.
