The grizzled giant squirrel is hunted for food and for its fur by forest-dwelling people, and an increasing local human population has caused even the activities of the forest people to become...
squirrels killing squirrels.
It's been told that there are cannibalistic gray squirrels out there, just as there are the same among hamsters, rats, gerbils, and cats when their babies are threatened....
squirrels don't communicate. i don't think, the only time that they do sorta communicate is when they are fighting over food. but sometimes they make little height sqeaking sounds at each other! p.s....