Vibrating rats!

[Mandy]

Sometimes when I'm petting my boys their whole body vibrates! Surely they can't be scared because they come up to my hand all the time :/
What does it mean?
Mandy x

 

[jorats]

I've always related it to some kind of fear or nervousness. Or perhaps pent up energy?

 

[Mandy]

Uh-oh, I'll let them have a big runaround and see how that helps. If it still happens, I'll have to consider a different approach to them. They are pet shop rats so they're not used to people at all poor things!
Mandy x