I am not entirely sure when my daughter mutated into a tigress, I suspect it must have been around the time that she started grabbing for things, but mutate she sure did.
And she has gotten even better these days, now that she has started crawling. She watches for her minute, and then, when no one is looking, lunges. If you watch very carefully, you can see her minute of lunging.
Well, if you are careful and whisk away the thing she lunges for, then just like a tigress, she gives chase until she catches it.