The mammal known to have the most active social structures is the dolphin, particularly species such as the bottlenose dolphin. Dolphins live in complex social groups known as pods, which can consist of just a few individuals or hundreds. Their social structures are characterized by cooperative behaviors, intricate communication, and strong social bonds. Dolphins engage in a variety of social activities, including hunting, playing, and caring for their young. These sophisticated social dynamics allow them to exhibit behaviors such as teamwork and problem-solving, reflecting a high degree of social intelligence that has fascinated researchers and marine biologists.