The main difference between animal emotions and human emotions is that animals don't have mixed emotions the way normal people do. Animals aren't ambivalent; they don't have love-hate relationships with each other or with people. That's one of the reasons humans love animals so much; animals are loyal. If an animal loves you he loves you no matter what. He doesn't care what you look like or how much money you make.

This is another connection between children and animals: children have mostly simple emotions, too. That's why normal people describe us as innocent. children feelings are direct and open, just like animal feelings. We don't hide our feelings, and we aren't ambivalent.

Emotionally, children are more like animals, because children's frontal lobes are still growing and don't mature until sometime in early adulthood.The frontal lobes are one big association cortex, tying everything together, including emotions like love and hate that would probably be better off staying separate. That's another reason why a dog can be like a person's child: children's emotions are straightforward and loyal like a dog's. A seven-year-old boy or girl will race through the house to greet Dad when he comes from work the same way a dog will. Animals and children have simpler emotions because their brains have less ability to make connections, so their emotions stay more separate and compartmentalized.(Excerpt from Chapter 3 of Animals in Translation by Temple Grandin and Catherine Johnson)  

Examples of child-animal interactions from a year-long ethnographic study of preschoolers are examined in terms of their basic nonverbal processes and features. The contingency of interactions, the nonhuman animal's body, its patterns of arousal, and the history of child-animal interactions played important roles in determining the course of interac- tions. Also, the children flexibly accommodated their interactive capaci- ties to the differences in these features which the animals presented. Corresponding to these observable features of interaction, we argue that children respond to variations in animals' agency, coherence, affectivity, and continuity. Recent research shows infants also respond to these dimensions in interactants. The implications are that for the young child, animals are social others that present intrinsically engaging degrees of discrepancy from human social others; and that the child's sense of self takes shape in the available interspecies community. Interacting with animals may be more primary than human-centered factors (such as cultural meanings, anthropomorphism, social facilitation, or psychodynamic processes) in the child's experience and developing un- derstanding of self and animal other. Implications for the theories of social development are discussed.