Dolphins are lovely animals, and they are relatively friendly to humans. For example, we often see dolphins in aquariums taking pictures with humans, and sometimes they kiss humans. In addition, their friendliness will be reflected in their rescue behavior, because they will push the falling water to the shore.
Researchers have studied dolphin friendliness and come to many different conclusions. Some researchers believe that this friendly attitude is due to their natural nature, because the natural instinct of large dolphins to take care of young dolphins is also reflected in their rescue behavior. Some researchers believe that dolphins can use ultrasound to tell that humans have lungs with the same structure as their bodies, so they can judge that humans are their own kind and therefore friendly to them. They can even identify pregnant women by echolocation, whether humans are injured and so on.
As mentioned above, dolphins are very friendly to humans, and they will save people who fall into the water. Biologists have studied this phenomenon to find out why dolphins save people. Some biologists believe that it is natural for dolphins to save people, because large dolphins often lift humans above the surface of the water by small dolphins, so that they can breathe more easily. Some biologists believe that dolphins save people because they are playing with humans. Other biologists believe that dolphins save people because they are intelligent, and that pushing humans to shore rather than to deep water reflects their intelligence.
