Studies have found that humans use the typical differences in infant and adult morphology as important behavioral clues. The characteristics of juveniles can evoke the loving and nurturing heart of adults. Many animals have the characteristics and characteristics of human infants. Attracted by animals, they are raised as pets. The most suitable explanation for this conclusion is:. ['Some people who are too nostalgic for their childhood will show a clear tendency to be childish in dress.', 'After the children grow up and leave the family. The old people like to keep pets. They care for love and pass the lonely time.', "For a long time, Disney artists have given Wen Liang's cute cartoon image Mickey Mouse an increasingly youthful appearance.", 'Children who are over-cared for in their lives will have a certain impact on their psychological growth and often behave more fragile.']