1. Nature: Dolphins are mammals that breathe with their lungs, and they are born with the instinct to take care of their companions. Human beings are equivalent to their cubs. When they face human beings, they will exude instinctive nature and become closer to human beings. In addition, they will use ultrasound to detect the surrounding objects, and they find that human beings, like themselves, breathe with their lungs, so they will treat human beings as creatures like themselves and be closer to human beings.

2, High IQ: Dolphins have relatively high IQ among marine creatures, and they have emotions like humans. When they get along with human beings for a long time, they will also have feelings and become closer to human beings.

Dolphins save lives based on their nature of caring for their children, because they are mammalian animals, and it is their nature to care for their children. Because the baby dolphins are not flexible enough when they are born, and they can't swim to the sea to breathe quickly, the big dolphins will lift the baby dolphins with their beaks, so that their pectoral fins can leak out of the water. When humans are found struggling in water, their nature will be stimulated, so they will lift humans up and send them to shallow water.