If they had hands

Evolutionary biologists believe that dolphins, if not superior, are not inferior to people in many aspects of development, but they have not been able to create huge cities and develop technology due to lack of hands.

In an article published in Nature Ecology and Evolution, a researcher from the University of Manchester, Suzanne Schulz tried to confirm or disprove the theory that the human brain is larger than other animals relative to body weight because people live in complex social groups. The theory says that the cleverest and most cunning members of society often won the favor of females, skillfully defended the group from external threats and replayed more powerful but stupid competitors. As a result, communities that had more intelligent members survived and developed.

Schultz argues that the hierarchical social structures of dolphins are practically an underwater version of the human society. Like other cetaceans, they call each other by name, communicate within a group in a special dialect, raise children and take care of the elderly. Also, scientists observe a wide range of all kinds of patterns of cultural and social behavior.

According to Schultz, dolphins do not have a detached thumb that allowed people to use tools in their activities, so they did not evolve to our level. Perhaps if several hundred thousand years ago the cetaceans managed to grow their hands, there would already be huge cities under the water.