The Rat Terrier is a breed of terrier developed in the United States from a wide mixture of Terrier and non-Terrier breeds. Originally bred as a working farm dog responsible for clearing farms of rats and mice, the breed is growing in popularity as a companion dog. The Rat Terrier was very common up until the 1930’s when it began to fall out of the public eye. In recent years, the breed has seen a major resurgence and is quickly growing in popularity. As major kennel clubs have begun to accept the Rat Terrier, there is increasing dispute as to what the ideal breed member is. Although many registries treat all Rat Terriers alike, there are already at least two distinct recognized breeds of Rat Terrier, the Rat Terrier and the Teddy Roosevelt Terrier or Teddy Roosevelt Rat Terrier, with the Rat Terrier coming in either two or three size varieties depending on the registry. There is also a third variety, the Decker Rat Terrier or the Decker Giant Rat Terrier that is almost unique enough to be a separate breed. The Rat Terrier is also known as the American Rat Terrier, Farm Terrier, and the Feist.
Developed as a working farm dog, in often remote areas, early Rat Terrier breeders cared very little for pedigrees or paperwork and placed the emphasis on working ability. As a result, much of the breeds early history was poorly documented leaving the creation of the Rat Terrier shrouded in some amount of mystery. About the only thing that is certain is that development of the Rat Terrier began with 18th century American farmers who wanted to create a small breed that was not only capable of controlling vermin such as rats and mice, but could also be used for hunting squirrels, hare, and other small game; this was accomplished by crossing a number of different terrier varieties, and also some non-terrier breeds.
Terriers are a very ancient type of dog, and have been present in the British Isles for hundreds, and likely thousands of years. Some of the earliest evidence for their appearance dates back the 1st Century A.D. Archaeological finds from the English/Scottish Border include Terrier-like dogs which were probably used to attack small mammals in their burrows. Although this is among the earliest solid evidence for the existence of Terriers, it is thought that they may be much older. Terriers were primarily kept by British farmers to exterminate vermin and occasionally for sport hunting. These dogs were bred to be ferocious killers of small mammals, tasked with eliminating essentially any wild creature their size or smaller. At various times, Terriers have been used to hunt essentially all mammal species in Britain smaller than the wolf, including rats, mice, badgers, foxes, otters, and mink. The small and short-legged Terriers have a unique ability among hunting dogs. They are capable of, and willing to pursue animals deep into their burrows to drive them out or kill them. It is this tendency that gives them their name; the word Terrier is based on the Latin word, “Terrarius,” and the French word, “Terre,” both meaning, “Earth or “Ground.” Terrier roughly means, “One who goes to ground.” Terriers served a valuable purpose, and were vital in preventing crop loss, starvation, and disease. For many centuries, Terriers were bred solely for working ability; appearance mattered only to the extent that it impacted the dog’s ability to do its job. Although there were many distinctive varieties of Terrier, they were regularly interbred and none were true breeds in the modern sense.
Terriers began to take on a somewhat larger role with the rise of fox hunting in the 16th and 17th Centuries. Prior to that time, foxes were considered unworthy game for the nobility, who greatly preferred the more ritualized deer and boar hunt. Increasing population, however, and massive deforestation in earlier centuries would mean that large game species would become extremely rare or would entirely go extinct. Without these larger game species, the British aristocracy would shift its hunting interest to the lowly to fox, and huntsmen would begin to breed terriers specifically to hunt this devious creature. Most earlier Terriers were short-legged, but those used to hunt fox were taller and somewhat larger. Although there were many strains of Fox Terrier that were relatively pure bred, even these dogs were not pedigreed until the 19th Century.
The first Terriers to arrive in America did so with its earliest colonists, probably sometime during the 1600’s. Both farm and hunting Terriers were imported into America, where they served the same purposes as they had in Britain. In an era where it was incredibly difficult and challenging to ship dogs across the Atlantic, relatively few British dogs arrived in the New World, and of those that did, they were regularly interbred with each other. The resulting dogs were a mixture of many different Terrier varieties. Most early settlers came from England, where smooth-coated Terriers were more common. As a result, smooth-coated Terriers came to predominate in America. American Terriers had to adapt to different conditions in their new home. The climate in America is generally much warmer than Britain, which also leads to a more disease. The terrain is also more varied and difficult, including large mountain ranges and vast tracts of dense swampland. Even the animal species are different, usually larger, faster, and more aggressive. As a result natural selection began to play a role in Terrier development, resulting in a hardy, disease-resistant dog, well-suited to life in America.
American farmers used their Terriers to exterminate rats and mice from their barns, silos, and fields, and also occasionally to hunt wild animals for food or sport. In the American South, it quickly became apparent that Terriers were very useful for hunting squirrels, and a number of distinct lines were developed specifically for that purpose. These squirrel hunting terriers became known as Feists. One of the first records of these dogs comes from 1770, when George Washington described a dog saying it looked like a Feist. Throughout the centuries, more and more Terriers were imported to America, along with a variety of hunting and sporting breeds. During this time many of the American lines were still in their infancy and American farmers and hunters were willing to introduce essentially any new breed or type into their breeding programs in the hopes of improving them. Although records were not kept of these breeding experiments a wide number of breeds were probably used, some are known with certainty and others can be guessed. Beagles were almost certainly added to increase hunting ability and sense of smell. Whippets and possibly Italian Greyhounds introduced greater speed. Manchester Terriers, Smooth Fox Terriers, Bull Terriers, Staffordshire Bull Terriers, and the now-extinct English White Terrier were very likely used as well. Other potential additions included Jack Russell Terriers, Pointers, and Cocker Spaniels. Some breeders greatly favored smaller Terriers, and in order to reduce their size introduced Chihuahua blood, and possibly that of the Dachshund and other Toy Breeds as well. By the end of the 19th Century, American Terriers and Feists had become quite distinct from their British counterparts. These American Terriers had to live in peace with children, farm animals, and other dogs. American breeders selectively bred those dogs that were most able to live in harmony with all creatures and family members other than their targeted prey of rodents, eventually resulting in a much softer temperament than most British Terriers. This softer temperament is also the possible a result of Beagle and Whippet blood.
In 1901, Theodore Roosevelt became America’s 26th President. Better known as Teddy, Roosevelt was an avid hunter. He was often accompanied on his hunting trips by a small pack of Terriers, most of which were black and tan. He brought one of these dogs to the White House with him, both as a companion and to exterminate rats. Named Skip, the dog was black and tan and short-legged. Teddy Roosevelt called the dog a Rat Terrier due to its proficiency at killing rodents, and the name stuck for the entire breed. There is long-lasting myth that Teddy Roosevelt’s Rat Terrier exterminated the rats from the White House. While that dog surely did kill its share of rats, most of the actual extermination work was done professionally by an exterminator that made use of both Terriers and ferrets. The President’s dog helped to popularize a breed that was already relatively common, and the Rat Terrier began to increase dramatically in numbers. For the first three decades of the 20th Century, Rat Terriers were some of the most numerous dogs in America, and were a very common sight on American farms. At the time, Rat Terriers were incredibly variable in appearance, and continued to be bred almost exclusively for working ability. It is said that a Rat Terrier holds the record for most rats killed in a barn, with the record holder supposedly killing 2501 rats in 7 hours.
The Great Depression of the 1930’s saw thousands of farmers lose their land, a situation which was made even worse by the Dust Bowl. This process continued with the rapid industrialization and urbanization that followed World War II, and with each passing year there were fewer and fewer farms for Rat Terriers to work on. Perhaps even more damaging to the breed, inexpensive and highly effective pesticides were developed making the breed less necessary. Rat Terrier numbers began to fall dramatically. Many sources claim that the breed became quite rare, but this is probably a great exaggeration. Although the Rat Terrier was less common than it had been previously, thousands of these dogs could still be found on the few remaining family farms, as well as in the South where they continued to be used to hunt squirrels.
Throughout the 20th Century, dozens of Rat Terrier registries were founded to keep pedigrees of these dogs, and many distinctive varieties were developed, especially of Feist. Many of these varieties were regularly interbred, although some were kept pure. Short-legged Rat Terriers eventually became known as Teddy Roosevelt Terriers, in honor of the President who popularized them. By the end of the 20th Century, the National Rat Terrier Association (NRTA) had become the largest and most influential Rat Terrier organization in existence, and also maintained the largest and most influential Rat Terrier studbook, the National Rat Terrier Registry. The NRTA divided Rat Terriers into four varieties, Toy, Mini, Standard, and Decker, based primarily on size. The NRTA considers all body styles and sizes to be different varieties of the same breed and all may be crossed. In 1972, a hairless Rat Terrier was born. Named Josephine, her owner Edwin Scott began to develop a new breed, the American Hairless Terrier. In the 1960’s, a hunter named Milton Decker acquired a 32 pound Rat Terrier named Henry. Decker was so fond of the dog that beginning around 1970, he traveled the entire country looking for the largest specimens of Rat Terriers. He began to breed these dogs and through his work and that of a few other breeders developed an entirely new variety, known as the Decker Rat Terrier or the Decker Giant Rat Terrier.
The NRTA wanted to maintain Rat Terriers as exclusively working dogs, and also to allow a slightly more open registry for health and working reasons. They were strongly opposed to having the Rat Terrier registered with the American Kennel Club (AKC) for a number of reasons. They felt that the AKC only cares about conformation, and that the working abilities of dogs registered with that organization suffer greatly. They also felt and in many cases justifiably so, that AKC dogs are often highly inbred and unhealthy. Perhaps most importantly, they feared that AKC recognition would greatly increase the popularity of Rat Terriers causing commercial dog breeders (puppy mills) and inexperienced backyard breeders to begin breeding low quality dogs. The NRTA and other Rat Terrier registries were less opposed to registration with the United Kennel Club (UKC), which has long put a much greater emphasis on working ability and is generally viewed more favorably with breeders of hunting and herding type dogs. Although the NRTA and most other Rat Terrier organizations were staunchly against AKC recognition, a smaller group of fanciers were strongly in favor of having the Rat Terrier recognized with the AKC. These fanciers formed the Rat Terrier Club of America (RTCA) in 1993, and began the long process of obtaining AKC recognition. The RTCA also worked to increase public awareness of the breed.
In 1999, the United Kennel Club recognized two distinct varieties of Rat Terrier as separate breeds, the Rat Terrier and the Teddy Roosevelt Terrier. The UKC also recognized two separate size varieties of Rat Terrier, the Standard and Miniature, including the NRTA Toy size in the Miniature. Initially, the United Kennel Club also considered the American Hairless Terrier to be a variety of Rat Terrier, but reclassified it as a separate breed in 2004. The UKC does not recognize the Decker Rat Terrier. Although the UKC treats the Rat Terrier and the Teddy Roosevelt Terrier separately, most Rat Terrier registries do not, and the UKC accepts single registrations for Teddy Roosevelt Terriers from at least 10 different registries where they are designated solely as Rat Terriers. Other than the UKC and AKC, most Rat Terrier registries refer to the Rat Terrier as the Type A Rat Terrier and the Teddy Roosevelt Terrier as the Type B Rat Terrier. The efforts of the RTCA also paid off on the public relations front, and the breed quickly became much better known. This fame, however, did come at a cost, and many of the NRTA’s fears were realized. Rat Terriers became increasingly sought after as a family pet, and commercial and backyard breeders began to exploit this popularity. Thousands of Rat Terriers are now bred in substandard conditions by people who care only about the profit, not the quality, health, or temperament of their dogs. It has become increasingly important to carefully select a Rat Terrier breeder, and most experts strongly discourage anyone from buying a Rat Terrier from a pet store.
In 2004, the RTCA successfully petitioned the AKC to enter the Rat Terrier into its Foundation Stock Service (AKC-FSS), the first step towards full AKC recognition. The AKC slowly began to allow the Rat Terrier to compete in more and more officially sanctioned events and the breed quickly earned a reputation for success at the highest levels of a number of AKC performance and companion dog events. In 2010, the Rat Terrier was officially added to the Miscellaneous Class, only one step shy of full recognition. Rat Terriers are now eligible to compete in almost all events that members of the Terrier Group are eligible to participate in, with the exception of conformation events. The RTCA continues to petition the AKC for full recognition in the Terrier Group, a status that will hopefully be granted in the next few years. Both the RTCA and the AKC do not consider Teddy Roosevelt Terriers/Type B Rat Terriers to be Rat Terriers, and do not recognize them. The RTCA/AKC will not even register dogs whose parents are known to be Teddy Roosevelt Terriers. The RTCA and AKC also do not recognize Toy Rat Terriers or Decker Rat Terriers, although their position on the descendants of these dogs is less clear.
Over the past decade, the Rat Terrier has continued to grow in popularity as a companion dog, and is becoming an increasingly common sight. There are now many thousands of Rat Terriers in the United States. Surveys and records conducted by the NRTA in 2004 included 338,919 Rat Terriers, with more than 26,000 registered annually. The dog is now commonly seen as an urban and suburban companion, and is now a regular entrant in a wide variety of canine events, ranging from earth dog trials to conformation shows. Rat Terriers, especially Decker Rat Terriers, have even successfully competed in schutzhund. For a modern breed, a very high percentage of Rat Terriers remain working dogs, and many thousands still serve as vermin eradicators and hunting dogs, tasks at which this breed excels. One of the most versatile of all breeds, Rat Terriers have also served in law enforcement, security, therapy, assistance for the handicapped, and entertainment. As the popularity of the breed continues to grow, it is very possible that the Rat Terrier will soon reclaim its place as one of the most popular dogs in America.
The Rat Terrier is generally similar in appearance to other smooth-coated Terriers, but still maintains a unique appearance. Both the AKC and the UKC recognize two size varieties of Rat Terrier which are identical in appearance other than size. The Miniature Rat Terrier stands between 10 and 13 inches tall at the shoulder and the Standard Rat Terrier stands between 13 and 18 inches tall at the shoulder. Weight should be proportional to height with Standard sized dogs usually weighing between 12 and 35 pounds and Miniatures typically weighing between 6 and 12 pounds. The NRTA also recognizes a Toy variety of the Rat Terrier. This size stands less than 10 inches in height and typically weighs between 4 and 8 pounds. No matter the size, Rat Terriers are all working dogs and should appear as such. This breed is among the most athletic of all Terriers and should be very fit and extremely muscular. Some of these dogs are so muscular that they could be described as chiseled. The Rat Terrier is slightly longer than it is tall, but not to a particularly noticeable extent. This breed should have long, straight legs, which hold it clearly off the ground. The tail of the Rat Terrier is traditionally docked to a very short length, often between the second and third vertebrae. However, this practice is falling out of favor and is actually banned in some countries. Many Rat Terriers have naturally bobbed or shortened tails, while others have medium-length tails that taper towards the end.
The head of the Rat Terrier sits on the end of a relatively long neck for a Terrier and is proportional to the size of the body, although those of smaller dogs may be slightly proportionately larger. The head is very similar to that of most Terriers, especially the better known Jack Russell Terrier. The head and muzzle combine to form a blunt wedge shape. Although clearly distinct from each other, the head and muzzle transition smoothly into each other. The muzzle itself is relatively but not excessively long, and also quite wide. This breed can open its jaws incredibly wide (necessary for killing rats) and has a surprisingly powerful bite. The color of the Rat Terrier’s nose is usually black, but may match the coloration of the dog’s coat. The eyes of a Rat Terrier are small, round, and somewhat prominent, and their color varies depending on the coat. One of this breed’s most distinctive features is its ears. The ears of most Rat Terriers are quite large, both in terms of length and width, and stand erect, either straight up or pointing slightly to the sides. However, many Rat Terriers have semi-prick, or folded ears as well, both of which are acceptable in the show ring. Some Rat Terriers, especially those from working lines, have two different ears, for example one prick and one folded although this is not preferred. The overall expression of most Rat Terriers is friendly and lively.
The coat of the Rat Terrier is short, smooth, and dense. Their coats should ideally have a sheen as well. Color is something of a controversy among Rat Terrier fanciers. These dogs are found in virtually every color and pattern found in any dog, and some registries accept any color. The AKC and UKC both place restrictions on colors in the conformation ring. The UKC demands that there be some white on the dog, although it may be located anywhere and be of any size. The UKC allows solid white, bi-color, and tri-color dogs. Acceptable UKC colors include black, tan, chocolate, blue, blue fawn, apricot, and lemon, any of which may have a sable overlay. The AKC demands that all Rat Terriers have some white on their body, but does not permit solid white dogs. AKC standards call for Rat Terriers to be between 10% and 90% white. The AKC allows black, chocolate, tan, fawn, red, apricot, lemon, and blue, any of which may have tan points. The AKC considers a black mask on dogs without other black markings a serious fault. Both the AKC and the UKC allow for ticking, but the AKC disfavors heavy ticking. Both clubs disallow merle and brindle markings. Rat Terriers are very frequently born with alternative markings. Such dogs may not be shown at AKC or UKC events, but make just as excellent pets and working dogs as other Rat Terriers, and most are eligible for completion in non-conformation events with those organizations or conformation events held by other Rat Terrier registries.
All varieties of Rat Terrier have virtually identical temperaments, although some individual lines are more driven than others. This breed is considered among the softest tempered and most adaptable of all Terriers, and is equally at home in the field or the home. In general, Rat Terriers are very people oriented. This dog wants to be with its family at all times, and most of these dogs are extremely affectionate. Rat Terriers can suffer from severe separation anxiety, but this is less of a problem than is the case with other breeds. Some Rat Terriers have a tendency to become one person dogs, but most will form equally strong attachments with all members of a family. Rat Terriers can be quite demanding of affection and attention, often to the point of being irritating. Those who do not like a toy being constantly dropped in their laps may wish to consider a different breed as Rat Terriers are extremely playful.
Rat Terriers are quite variable in their reactions to strangers. Some breed members are very friendly and greet everyone warmly and eagerly. Others are considerably more reserved. Although timidity and human aggression are rare in Rat Terriers, they have been seen on occasion, mainly in commercially bred lines. Those Rat Terriers that are more reserved can take a while to form attachments to a new person such as a roommate or spouse, but most come around eventually. Rat Terriers are highly alert and make capable watchdogs. Although this breed is neither large nor aggressive enough to make an effective guard dog, some have been trained for personal protection.
Rat Terriers are perhaps the most accepting of all Terriers when it comes to children. When properly socialized, this breed is generally very tolerant of children and is much less snappy than most other Terriers. These dogs often form very close bonds with children, especially family members, and love the attention and play that they provide. Rat Terriers that have not been socialized with children are usually considerably less tolerant, and often prefer to avoid them and their loud noises, rough handling, and jerky movements. Although the Rat Terrier is quite tolerant, owners do need to be aware that this is still a Terrier, and most will defend themselves if they feel it is necessary to prevent abuse.
Rat Terriers are generally accepting of other dogs, and most have few issues with them. Many breed members actively seek out canine company and greatly prefer to share their lives with at least one other dog. This breed is somewhat protective of its toys, food, and similar, “possessions,” and scraps can sometimes develop. Rat Terriers sometimes develop aggression issues with strange dogs, but these can mostly be worked out through training. Owners do have to be aware that although Rat Terriers rarely go looking for a fight, they’ll gladly take one if it comes their way. This breed will not back down from any challenge, no matter the size of the opponent, which can result in disaster. As a farm dog, Rat Terriers needed to be dependable with livestock, and once properly socialized, most breed members do just fine with animals their size or larger such as cats, chickens, and horses. However, Rat Terriers have an incredibly strong prey drive and are driven to attack and kill anything smaller than themselves such as rats, hamsters, or guinea pigs. When left alone outside for any length of time, a Rat Terrier will probably bring its owner back, “presents” of dead lizards, rodents, insects, and birds.
Rat Terriers are extremely trainable, perhaps the most trainable of all Terriers. This breed is accomplished at a number of canine events, including agility, obedience, and more rarely schutzhund. The Rat Terrier is considerably more biddable and willing to please than most Terriers, and is also highly intelligent. Although this breed is much more trainable than most Terriers, it is still a Terrier and can provide substantial training difficulties. Many Rat Terriers are stubborn, and will refuse to perform tasks that they do not wish to. Easily bored, Rat Terriers often tire of repetitive tasks to the point where they will not continue to perform them. This breed also has a tendency to exhibit selective listening and obedience, choosing when it will and will not follow instructions. Owners who utilize rewards-based training methods will have the most success working with this breed, as will those who maintain a consistent position of dominance.
Rat Terriers are highly energetic dogs and need quite a bit of activity. This dog needs considerably more exercise than most breeds their size, at least 30 to 45 minutes a day. This is the minimum, and a Rat Terrier can take as much activity as it is provided. Although this breed can get by with a long walk, they are happiest when provided more vigorous activity. Rat Terriers make surprisingly good jogging companions, and also participating in a number of canine events. It is absolutely vital that a Rat Terrier be provided with a proper outlet for its energy, otherwise it will surely find one on its own. Unexercised Rat Terriers are very likely to develop behavioral issues such as destructiveness, excessive barking, hyper activity, and over excitability. That being said, the Rat Terrier does not have extreme exercise demands and a reasonably active and committed family should be able to meet their needs without being overly burdened. Many families actually greatly enjoy this breed’s energy and athleticism. With the possible exception of the Jack Russell Terrier, there is perhaps no breed of this size that is as hardy and capable as the Rat Terrier. Always ready to go on any adventure no matter how extreme, Rat Terriers are eager and able to accompany their owners on virtually any excursion, from mountain climbing to surfing. No matter where they go, it is highly advisable that Rat Terriers be kept on leash at all times, as they have a strong tendency to chase small animals.
Potential owners need to be aware that while Rat Terriers make charming and affectionate companions, this is not a mild-mannered or dignified breed. In fact, Rat Terriers are among the “doggiest” of all dogs, and it could be said that a Rat Terrier, “will not let you forget that you own a dog.” This breed loves to run around outside and get as dirty, only to track it all in the house afterwards. Rat Terriers will jump up and lick faces unless carefully trained not to. This breed absolutely loves to dig, and will completely destroy a yard if given the opportunity. Many Rat Terriers cannot be trained out of this tendency and have to be provided a “designated digging area.” Of greatest concern for many owners is the dog’s barking. Although not as extreme as some other Terriers, Rat Terriers are much more vocal than most dogs. Even though it is unfair to describe a Rat Terrier as “yappy,” the bark of this breed is very high-pitched and usually repeated in quick succession. Training and proper exercise can greatly reduce a Rat Terrier’s barking, but it cannot eliminate it.
Rat Terriers have extremely low grooming requirements. This breed never requires professional grooming, only regular brushing and an occasional bath. Other than that, Rat Terriers only require the routine maintenance procedures that all dogs do such as teeth brushing and nail clipping. Rat Terriers do shed, and most shed quite a bit. Although some shed less than others, many Rat Terriers are heavy shedders who will cover furniture, clothes, and carpets to an amazing amount for a dog of this size. Allergy sufferers or those who simply hate the thought of cleaning up dog hair would be best advised to consider a different breed.
Rat Terriers are generally regarded as being an extremely healthy breed. This dog suffers from fewer health problems that most pure bred dogs, as well as lower rates of most common genetically inherited defects. In 2004, the NRTA conducted an extensive health survey of the breed, and found that the most common problems experienced by Rat Terriers were demodicosis, seizures/fits/epilepsy, bad bite, luxating patella, and allergies, although none were experienced by more than 2.6% of study participants. Potential owners must be extremely wary of dogs from commercial breeders and pet stores, as such animals are likely to have significantly reduced health than other Rat Terriers. The Rat Terrier benefits from having a large gene pool, as well as having been bred almost exclusively as a working dog until the late 1990’s. Any dog with a genetic defect would have been less capable of performing its job and would have been excluded from the gene pool. Due to their good health, small size, and general hardiness, Rat Terriers are among the longest-lived of all dogs. With proper care and nutrition, Rat Terriers have a life expectancy of between 14 and 16 years, and it is not especially uncommon for them to reach 17 or 18.
By far the most common problem experienced by Rat Terriers is demodicosis, also known as demodectic or Demodex mange. Almost all dogs have a species of mite living on their skins known as Demodex canis. This mite is acquired by nursing puppies from their mother, and usually causes no problems. Some dogs have an immune system response to the mite, which usually results in reddened skin, itchiness, and hair loss. The problem usually affects only a small patch of a dog’s skin, but may impact the entire body. Demodicosis usually makes its first appearance between 3 and 12 months of age. This condition is not contagious to other animals or people, and is almost always treatable. Mild cases often do not require medical treatment at all, and even moderate cases can be treated relatively easily. Severe generalized demodicosis can be very difficult to treat and can require lengthy and expensive treatments, in addition to causing severe misery for the dog.
Although skeletal and visual problems are comparatively rare in this breed it is still advisable for owners to have their pets tested by both the Orthopedic Foundation for Animals (OFA) and the Canine Eye Registration Foundation (CERF). The OFA and CERF perform genetic and other tests to identify potential health defects before they show up. This is especially valuable in the detection of conditions that do not show up until the dog has reached an advanced age, making it especially important for anyone considering breeding their dog to have them tested to prevent the spread of potential genetic conditions to its offspring.
A full list of health problems that have been identified in Rat Terriers (although admittedly at low rates) would have to include: