A Pomeranian and Jack Russell mix is called a Jack-A-Ranian (also spelled Jackaranian). It is a type of hybrid dog because it originates from two different breeds.
The Jack-A-Ranian is small and weighs between 6 and 14 pounds. These dogs come in various different colors including white, black, grey, red and brown. They tend to resemble the Jack Russell Terrier more in face and body structure, but retain some characteristics of Pomeranians. Jack-A-Ranians are friendly dogs that enjoy the company of their owners and usually get along well with other pets after they have been socialized. They have a tendency to bark at changes in surroundings, and therefore make good watchdogs.