A border collie and Jack Russell terrier mix, also known as a border jack, is the product of two intense canines. Both of these breeds thrive on work, and lots of it. They require an owner who can put in a lot of time and energy into training and finding an outlet for all that canine enthusiasm. If there's not an outlet for that tremendous canine drive, destructive behavior is almost inevitable. Expect your border jack to share your life well into his teens.
At maturity, the border collie stands between 18 and 22 inches tall at the shoulder, with males larger than females. The Jack Russell terrier is much smaller, standing between 10 and 15 inches high. The border jack will likely grow between 13 and 18 inches tall, although the dog could be larger or smaller.
The border collie breed standard permits any color, while Jack Russell terriers are predominately white with black, brown or tan markings. The Jack Russell terrier has either a smooth or wire coat, while the border collie has either a smooth or rough coat, the latter a medium length. The border jack may have a smooth, rough or wire coat, and generally has a great deal of white on the body. He might have the V-shaped dropped ears of the Jack Russell terrier, or the erect or semi-erect ears of the border collie. The Jack Russell carries his short tail high, while the border collie's tail is long and low.
Both breeds are smart dogs -- the border collie almost scarily so. While the Jack Russell famously dislikes other dogs and considers cats vermin suitable for killing, the border collie usually gets along with other canines and doesn't mind felines -- although he may try to herd them. Socialize your border jack early on with other dogs to see which side of the spectrum he inherited. Expect a good watchdog with a strong territorial streak, another trait of both breeds.
Border jacks are extremely active and need a job. Both dogs take easily to training and love to learn. Remember that these two breeds were developed for distinctly different tasks. The border collie lives to herd, and there's no dog surpassing him in this regard. The Jack Russell terrier lives to hunt, and possesses all the digging instinct of an earth dog. Take your border jack to obedience training early, and make sure he gets plenty of exercise. He could excel at agility and especially flyball. Your choice depends on whether he's more of a hunter or herder. Whatever you do, keep this dog busy.
Your border jack comes from two relatively healthy breeds, but watch out for certain disorders. Border collies are prone to various genetic eye issues often found in collies, while Jack Russell terriers may suffer from cataracts, glaucoma and progressive retinal atrophy, the latter rendering the dog blind. Some Jack Russells are born deaf. Hip dysplasia, a malformation of the hip joint, is common in border collies, while Jack Russell terriers may develop luxated patellas, or slipped kneecaps.