you must create an user event, an example is in the "Simple 3D Chat" on the ANET Homepage.
With an userevent you can send events like "client connected" or "client synchronized" with an string and the id of the user.
I would send an user event with a string of the lenght of 1.
the string contains e.g. "y" for yellow or "r" for red.
Now you can change the color of the animal on all clients.