Animations in the java models

I am working on a mod that is going to add some more creatures to the game, I added a crocodile, and I wanted it to have an animation for closing and opening its mouth, the problem is that with the animations that are available in MCreator, i just cant do what I wanted, is there any way to modify the animations?

For example, can I use the "Right Leg Swing Animation", and make it swing less?