The Behemoth does not want to play, have fun with your tummy issues though.

That said, while the boys are camping because Beat had to go and eat a glowing mushroom (dogs, right?), The Behemoth will in fact hang around and watch them. Without the bone ring from the store, she'll be hard to communicate with unless Josh knows Speak With Animals or some spell equivalent of that (I don't presume to know his life), but she'll sit there and listen to him.

It seems she understands him regardless of having the bone ring or not.