Jack Rat Terrier

Linda Simon
Dr Linda Simon (MVB MRCVS, University College Dublin)
Photo of adult Jack Rat Terrier
heatherintheusa / Flickr.com

The Jack Rat Terrier is a cross of the bouncy, feisty Jack Russell Terrier and the energetic Rat Terrier – two similar pedigrees that look very alike. Both are small, feisty breeds with larger than life personalities and lithe, muscular bodies. The Jack Rat Terrier can make a good family pet once sufficiently exercised but can be full-on and most are yappy and easily distracted when outdoors.

Both parent breeds have a similar look: small and compact with a handsome face and straight limbs, ideal for running. As the Jack Russell has button or drop ears and the Rat Terrier has larger, erect ears, the Jack Rat Terrier can inherit either. While Jack Russells will not always have white on their coat, most Jack Rat Terriers will. Though some will have their tail docked, in recent times, this practice has been frowned upon and it is now not unusual to see a Jack Rat Terrier with a long, slender tail.

About & History

Jack Rat Terriers are not particularly popular, and it is unclear both where and when they first originated. All of the designer dogs originated within the last 50 years or so but it is likely that the Jack Rat Terrier was first bred several decades after the first hybrid. Their parents each have a long and interesting history which we can take a closer look at.

The Jack Russell Terrier

Jack Russell Terriers were traditionally used as working dogs so had to be tenacious and hard-working. They were expert ratters and were employed in a number of places, including mills, factories and mines. It was the Fox Terrier that gave rise to the Jack Russell, which was first bred in England, though was soon brought to the United States where it was further refined.

Interestingly, they were only recognised by the Kennel Club within the Terrier group as late as 2016. This is because the breed had been run independently by other groups for a very long time. They are a well-known breed in the UK today and are kept as pets, as well as competitive spot dogs, as they excel in a range of disciplines, including canine agility, Frisbee and flyball.

The Rat Terrier

Rat Terriers are a sturdy dog with a vivacious personality and a drive to keep active and a strong desire to be part of the action. Breed fanciers wanted them to be fast and this was one of the most important criteria when breeding from them. Among other breeds, the Toy Fox Terrier, Whippet and Manchester Terrier were used to contribute genetics to this breed.

It is thought that they were brought to the States from the UK and it was within America that they were refined to have a superior sense of smell and to become even faster. One of their most popular progeny is the American Hairless Terrier, which is a completely bald Rat Terrier.


Jack Rat Terrier Large Photo
Dustin Gaffke / Flickr.com

Jack Rat Terriers are true athletes, with stocky and well-muscled bodies that are built in proportion. They have no exaggerated features and should be well-balanced. They have a handsome face with a medium-sized skull and ears that may or may not be held erect. Their eyes are a dark brown and almond in shape.

Their forehead is relatively flat and they have expressive ‘eyebrows’. For a small dog, they have a good-sized muzzle and should have a neat, scissor bite. Their bodies are longer than they are tall and they have straight and solid limbs. Tail docking continues to be practiced in some countries, but their natural tail is quite long and may be curled at the end.

A fully-grown Jack Rat Terrier weighs from 9kg to 12kg and measures from 33cm to 45cm. Females are usually somewhat slighter and lighter than their male counterparts. The Jack Rat Terrier has a short, straight and smooth coat, which can shed quite a lot. Dogs can be a combination of blue, white, tan, brown and black and most are either bi-coloured or tri-coloured.

Character & Temperament

The Jack Rat Terrier is a bit like the Duracell bunny in that it just keeps going and going and going… They seemingly have no off switch and some owners (particularly those that have never owned a dog before) can find them too much to handle. They have a real zest for life and their cheery nature is contagious. They are naturally curious and keep themselves busy and active by exploring their home and garden almost non-stop.

Good-natured and keen to make those around him happy, the Jack Rat Terrier can get on well with people of all ages but may be a bit too exuberant for younger children. Some are snappy, particularly when young, so this needs to be taken into account. They can be territorial within their home and may be suspicious of new people.

The prey drive in the Jack Rat Terrier remains high and they have a natural urge to seek out and hunt small animals, such as rodents and squirrels. This means that their gardens must be well-fenced and they typically need to be kept on a lead at all times when in public areas unless their recall is excellent.


Photo of Jack Rat Terrier puppy
Firas Wehbe / Flickr.com

Jack Rat Terriers are smart, responsive and eager to learn. As they were bred to work, they love to use their brain and to complete tasks when asked. Versatile, they excel in a number of areas and can be trained in obedience, agility and many other disciplines.

A lack of training can result in a difficult dog that fails to listen to their owner and can be difficult to control. Their training needs to begin from an early age and should continue throughout their adult life. Anecdotally, they are quick to house train.


Robust little dogs with a hardy disposition, Jack Rat Terriers typically enjoy good health. Despite this, we are aware of a number of health issues, which they may develop.

Patellar Luxation

Terriers are especially prone to luxating patellae. When the knee joint is not in place, it can cause lameness and localised pain. Many dogs will be managed with a combination of pain relief, anti-inflammatories and hydrotherapy. For some, surgery is needed to relieve pain and improve mobility.

Heart Disease

Patent Ductus Arteriosus (PDA) & Mitral Valve Disease (MVD) are two heart conditions, which can plague the Jack Rat Terrier. PDA is an inherited defect of the heart, which is present from birth, while MVD is a progressive heart disease that tends to present in middle-aged to older dogs.

Tracheal Collapse

Many owners will initially confuse a collapsing trachea for a condition, such as Kennel Cough. However, this cough will not go away and will in fact get worse over time. Imaging studies can diagnose this disease. Over-weight dogs should lose weight as soon as possible to alleviate symptoms and owners should try to use body harnesses rather than neck collars when walking their dogs.

Atopic Dermatitis

A dog with itchy skin should not be assumed to have atopy as there are many other potential causes, including bacterial, yeast and parasitic infections. Allergies can cause chronic itchy, red skin and are notoriously difficult to control.

Exercise and Activity Levels

Though small in stature, the Jack Rat Terrier has a high exercise requirement and owners need to be committed to providing at least 90-minutes of exercise each day. This should not be boring and monotonous and, instead, should be varied. Dogs should be brought to a number of different locations and be allowed to sniff away to their hearts content. Many owners are surprised at just how much stamina they have.

An under-exercised Jack Rat Terrier is no fun at all and will quickly become destructive within the home and/or garden. They may release their energy by barking non-stop, digging, chewing or scratching at furniture.


The very short fur of the Jack Rat Terrier does not get matted but these dogs shed an awful lot so should be brushed every day during warmer weather to reduce the amount of fur lost within the home.

Those with pendulous ears should have them cleaned out as needed using a specific canine ear cleaner. When possible, owners should brush their Jack Rat Terrier’s teeth on a daily basis to minimise periodontal disease.

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