Excerpt from the Analysis of a Dog Phobia

At a certain period in their development, nearly all children show a transitory fear of one animal or another. Many of these fears are overlooked because they cause slight disturbance, or they are treated lightly and quieted in the usual way. Often they disappear spontaneously—are "outgrown" without any disturbing recurrence. It is only when a child's fear of certain animals radically disturbs its relationship to its environment that a psychotherapeutic treatment is resorted to; as, for example, when its fear prevents it from leaving the house or imposes some other more subtle limitation on its psychic freedom.

In Totem and Taboo Freud explains why it is that animals can so easily become objects of childish fear:

"The relation of the child to animals has much in common with that of primitive man. The child does not yet show any trace of the pride which afterwards moves the civilized adult man to set a sharp dividing line between his own nature and that of all other animals. The child unhesitatingly attributes full equality to animals; it probably feels itself more closely related to the animal, in the freedom with which it acknowledges its needs, than to the undoubtedly mysterious adult.

Not infrequently a curious disturbance manifests itself in this excellent understanding between child and animal. The child suddenly begins to fear a certain animal species and to protect itself against seeing or touching any individual of this species. There results the clinical picture of an animal phobia, which is one of the most frequent among the psychoneurotic diseases of this age and perhaps the earliest form of such an ailment. The phobia is as a rule expressed towards animals for which the child has until then shown the liveliest