The Jack Russell Terrier is a small, sturdy and tough Terrier that is also known as the Rebel Terrier or the “JRT”. The breed was developed in England some 200 years ago. Previously hunting dogs, the breed has now been featured in a number of TV and film projects because of their impressive level of intelligence and ability to perform tricks. The breed excels in agility, performance and tracking trainings.
They are surprisingly small but possess impressive levels of energy. The Jack Russell Terrier has a powerful and well-structured jaw. Their almond-shaped eyes are normally dark in color and their coats are smooth. This breed is known to be either white, tan, brown or black in color.
Jack Russell Terriers are merry, cheerful and loving dogs. They are friendly and enjoy children, but will not tolerate abuse or teasing from them.  On the other hand, this type of Terrier may not get along well with other small animals. Afterall, they are still Terriers! The Jack Russell Terrier tends to outshine the hunting instincts most other Terrier breeds. 
This breed is also known to be extremely athletic, vocal, and fearless. When left alone, they easily get bored, and may entertain themselves by becoming a nuisance. Therefore, it is important the owner has ample time to train and play with their Jack Russell Terrier.
Considering this Terrier’s impressive intelligence, the owners must be able to exercise control and authority over these dogs. Owners must also be strong-willed and consistently reinforce training exercises in order to avoid ending up with a defiant Jack Russell.  This is the main reason why many experts suggest dog owners of this breed enroll their dog in obedience workshops.
Jack Russell Terriers can be happy in apartments as long as they get adequate daily exercise. A long and brisk walk can provide sufficient exercise for this dog. However, experts advise that they live in a home with a fenced-in yard. Failure to give them physical and mental stimulation may trigger them to act out destructively.
In regards to grooming, the coats of Terriers are relatively easy to care for. Regular combing and brushing is enough, while only bathing them when necessary. This energetic breed is normally free from serious health conditions. The general good health of this breed has resulted in a longer than average life expectancy, about 15 years. 
 D. Caroline Coile, The Jack Russell Terrier Handbook (Barron’s Educational Series, 2000).
 Catherine Romaine Brown, Jack Russell Terrier: Your Happy Healthy Pet (John Wiley & Sons, 2006).
 Silvan R. Urfer, Kimberly Greer, and Norman S. Wolf, “Age-Related Cataract in Dogs: A Biomarker for Life Span and Its Relation to Body Size,” AGE 33, no. 3 (September 1, 2011): 451–60, doi:10.1007/s11357-010-9158-4.