Shaking Jack Russel

Question
We have two ten-month old jack russel females, and the one's never done this at all. Bristol's perfectly fine, but her sister Charlotte does it on and off occasionally. She'll shake, like shivers, but she's not cold as far as I can tell. Our house is pretty warm so it shouldn't be that. She did it when she was much younger (two or three months old) and it doesn't seem to bother her as she still wants to give kisses and climb all over people while it's going on, but I'm just curious as to what it actually is because I can't find much of a straightforward answer.

Answer
Hi Katie,
Dogs, like people, have individual personalities. Some can be more sensitive than others. If you have a pair of siblings taken from their mother earlier than 8-10 weeks you may have socialization problems. This is not necessarily a health issue but one may need more attention than the other if it is less dominant. Just let her grow and give her a good food and supplements. Have her examined at 12-18 months but realize it just may be who she is.
I consulted with a a top JR breeder about this who doesn't think it's common but I have seen many terrier puppies outgrow it or have it for a lifetime- it does not mean it is a problem.
Try thunder shirts- a t shirt that hugs the body mimicking protection.
Speak with your vet if other symptoms give you cause for concern.
good luck.