Hmm. A hypothesis worth considering. It's entirely possible he's completely untameable.

[ He claps the fingers of one palm against his hand and Indrik immediately disentangles himself from Adelaide's legs, to come sit by Rex- holding his head high enough for Rex to place the palm on the tip of his snout. ]

On the other hand, he responds to me in some ways.

[ Though his hand shoots up after Indrik's big ol' tongue just blepped him. ]