What is a neither terrier as in headhunters by Jo nesbo?

Oh, dude, a "neither terrier" in "Headhunters" by Jo Nesbo is just a made-up breed of dog. It's like if someone said they had a "fluffernutter retriever" or a "schnitzel spaniel." It's all just part of the fictional world of the book, so don't go looking for one at the pet store!