Teacup Dog Health

According to mainstream dog media, teacup size dogs are notoriously unhealthy. While evidence shows this is true to a large extent, there are breeders who have the right genetics and are producing healthy dogs.

Imperial Shihtzu photo courtesy of Tony Dougia of www.imperialshihtzus.com.
Imperial Shih Tzu photo courtesy of Tony Dougia of www.imperialshihtzus.com.

There are other breeders, however, who are primarily responsible for this bad reputation. These breeders—and there are many of them—do not understand there is a genetic difference between a teacup and a toy size dog in any breed that has a true genetic teacup size. Therefore, many breeders who do not have the right genetics in their breeding stock try to “bantamize” toys, resulting in what is called a “Tiny Toy.” The second reason is that most breeders who produce dogs with the correct teacup genetics also try to bantamize the teacup.

“Bantam” refers to any miniature size variety of a domestic breed of birds such as chickens and ducks. Thus, in the biological sense, the term “bantamize” is sometimes used incorrectly because it implies breeders can produce a bantam breed (smaller size variety) by continuing to cross the smallest members of an interbreeding population. However, breeders cannot produce bantam size varieties of chickens and ducks in this way unless there is a certain kind of mutation on a specific gene, which very rarely occurs. This process produces one less repeated DNA sequence on the asp  gene than it does on the gene of the regular size variety. This is just like a miniature (or toy) size variety of a dog breed having one less such repeated DNA sequence on the gene than would the regular size members of the breed. Learn more about my theory on this in “Macrogenes and the Dog.”

There is a sweet spot in any size of the dog where agility, speed, strength and endurance are at an optimum. These sweets spots are at about 3.7 and 7.5 pounds in the teacup and toy sizes, respectively. It is possible to reduce the weight range of a breeding population of a teacup and a toy to 2–4 and 4-8 pounds, respectively, from the ideals of 2½ –5 and 5-10 pounds. It appears from information in breed standards discussed in “Macrogenes and the Dog” that any teacup or toy lighter than 2 or 4 pounds, respectively, is more likely to have health problems than dogs in the middle of the range. These health problems fall into five main areas.

Five Health Problems Resulting from Dog Bantamization

  1. Hypoglycemia from low blood sugar.
  2. Too thin bones, resulting in what the dog fancy describes as “weedy”—dogs with too little substance or bone and bones that are susceptible to breakage.
  3. For many dams under 5 pounds, the inability to self-whelp, meaning they often require Caesarians.
  4. For females, wombs that are reduced in size restricting the ability of the pups to grow properly before birth.
  5. Further complications to the two previous gynecological problems arise when there is more than one pup in the litter.


A Whippet wearing a coat to keep warm.
A Whippet wearing a coat to keep warm, due to a lack of an adequate layer of adipose tissue under its skin.

The Whippet, which is a medium, is bred for racing. Therefore, breeders have produced the fastest Whippets they can, resulting in many Whippets who shiver because they lack an adequate layer of adipose tissue under their skin that serves as insulation. Shivering is a physiological way mammals produce heat to keep warm when they are too cold.

Hypoglycemia in the dog is almost exclusively confined to small breeds that have been bantamized.

Bantamization results in the loss of adequate adipose tissue causing many teacup puppies to become susceptible to hypoglycemia. These pups need to eat every four hours or they run out of glucose, which fuels the brain and therefore resulting in coma and even death when there is an inadequate supply. White adipose tissue temporarily stores fat after meals, which can quickly reenter the blood stream to supply energy for muscles. This preserves glucose for the brain. Glucose can also be temporarily stored in the liver. Therefore, breeders who have the right genetics should, over time, stop breeding teacups who are susceptible to hypoglycemia. It remains to be seen the extent to which this can be done. Certainly “regular size” toy Poodles are not reported to have this health problem., but Tiny Toy Poodles often do have it.

Bone Health

The problem of fragile bones due to lack of substance is easy to  fix. However, small dogs have thinner bones than larger ones. Nevertheless, dogs with too little substance have both thinner bones and less muscle. Therefore, the ribs and other bones are more prominent when looking at a smooth coated dog like the Toy Fox Terrier. However, a buyer can get a good understanding of the substance of a rough coated dog like the Pomeranian, Yorkie or Poodle by just feeling the ribs and other bones.

Do you see the difference between healthy and unhealthy bone?

A fox terrier, considered "weedy" or with fragile bones.
A Toy Fox Terrier considered “weedy,” or with fragile bones. It lacks substance hrough bantamization.
A fox terrier with healthy bones.
A miniature Smooth Fox Terrier with healthier bones. It has adequate bone because its size variety has not been bred down to near its selection limit.

The Toy Fox Terrier on the far left is a prime example of a “weedy” dog with fragile bones. Notice the thin legs with inadequate muscles. This particular dog has a lack of a quantitative trait, which the dog fancy calls “substance,” often using the term “bone” to describe. This dog has thin, inadequate bone. The Toy Fox Terrier have been reduced in size to 3 1/2 to 7 pounds. It is too far from the sweet spot for its size of around 7 pounds. Any breed that has been reduced in size to this level will produce some unhealthy dogs such as this one with thin, fragile bone.

The miniature Smooth Fox Terrier featured to the right of the Toy has good substance or bone. These dogs were selected for their speed to try to keep up with the Foxhounds and the horses on the hunt. When the fox darted into a fox hole, the terriers would catch up, they are small enough and have the instinct to enter the hole to bolt the fox—and the chase was on again. Smooth Fox Terriers still average about 17 pounds. Since this weight is close to the sweet spot of 15 pounds for the miniature, these dogs have a much better chance of having strong bone than do the Toy Fox Terriers.

The widely used expression “fox in the henhouse” refers to the days when people tried to keep the local fox population under control, folks like my grandmother and aunt, who kept a chicken coup for fresh eggs and an occasional chicken in the pot. That is why people like George Washington and Thomas Jefferson often went fox hunting and actually used both larger Foxhounds for speed and smaller Fox Terriers for bolting the foxes. You can learn more about the history of fox hunting in the U.S. at Masters of Foxhounds. However, modern fox hunters in America, who do it for sport, do not use Toy Fox Terriers. The Toy Fox Terriers were too small to keep up with the horses, so people reduced them down as small as possible, but dogs with thin, fragile bone are still produced.

Fox hunters today use the larger Wire Fox Terrier, which is the same size as the Smooth Fox Terrier. The rough coat of the Wire Fox Terrier protects them better from briars than the smooth coat of the Smooth Fox Terrier.

Nevertheless, ethical teacup breeders advise potential clients with small children that they should consider a larger toy size dog. This is why, as I mention in my Introduction, I challenge the Chihuahua Club of America to recognize the Toy Chihuahua and define the Teacup Chihuahua in their breed standards. The Chihuahua Club of America should decide once and for all whether it will continue to side with the fundamentalist religious sects that do not believe in evolution or belatedly join the 20th Century and admit that there is a genetic difference between a teacup and a toy Chihuahua as many breeders have known for decades.

Gynecological Complications

The three gynecological problems are all related and complicated by the fact that some Saint Bernard litters can consist of more than 20 pups. Many smaller dogs have litters with eight to 10 pups, while many small toys have just one. Breeders will just have to see to what extent they can get better results by selective breeding to avoid Caesarians and other such gynecological problems with the knowledge presented here. Informed buyers can help this process by being more discriminating when choosing a breeder to deal with and what pup to buy. We will have to see to what extent the bantamization process reduced the size of the wombs of some potential dams.

However, there is evidence that my theory that the bantamization process has reduced the size of the wombs of some dams. A least one woman has been told my her doctor that she has a small womb. She has had two children, both by Cesarean.

Finding the Right Breeder

Therefore, unless you are a Hollywood celebrity, as opposed to just an average Jack or Jill, one should buy from a breeder who allows you to inspect the kennel and the parents, provide a pedigree with weights and offer some kind of guarantee. Pet stores and the operations that advertise all their satisfied Hollywood celebrity customers will not be as selective with the average Jack and Jill as they will be with the celebrity customers they love to tout. Therefore, you might wind up with a downsized toy with health problems instead of a true teacup. However, one must be aware of all of the potential problems with these small dogs and take them into consideration when choosing a breeder and a puppy.

An honest breeder will display on their website that they have the right genetics. Please seeTeacup Breeders” for what to look for when choosing a breeders. Breeders should demonstrate that they understand the genetics and what they have done or are currently trying to do to improve their breeding stock. Some may have already solved some of these problems. Hopefully, over time some of these problems can be eventually solved in all of the very .small size varieties  of the different breeds.