Black is neither a breed standard nor alternate color for Jack Russell terriers recognized by the American Kennel Club. The accepted breed standard color is a white base coat with markings that can be black, brown, cream, tan or tri-color. There are no accepted alternate colors or markings.
The Jack Russell terrier is a small breed that can reach up to 15 inches in height and weigh up to 18 pounds. They can live around 15 years and are typically healthy dogs, but they do tend to have hip, elbow and knee problems. They can also suffer from deafness and eye issues.