Cat vs Lion

How can someone be afraid of a cat but not a lion?  Levi is super afraid of our friends puppy, but not afraid of Gus!

 Zack and Lucas playing Mario Cart

Zack's puppy

 At least once every evening I look over and find all three of my boys playing on the floor together! Notice the little scab on Levi's forehead? :( He fell forward on my rug outside and it is a gritty material and it skinned it :(

How can he not be afraid of a great big black clumsy lion and not be afraid of that little yellow puppy (cat size)?