Fear of: animals.
Zoophobia is the most common type of phobia directed toward a specific person, place, or thing. Zoophobia encompasses many different animal fears, from arachnophobia (fear of spiders) to ophidiphobia (fear of snakes) to cynophobia (fear of dogs).
Sometimes, these phobias are caused by a traumatic experience with the animal as a young child, and can fade as a child grows up.