Great Dane. "Dogge Odin." Licensed under CC BY-SA 3.0 via Commons.
Great Dane. “Dogge Odin.” Licensed under CC BY-SA 3.0 via Commons.

By Russell Schexnayder

There are seven genetically based, biological sizes of dogs revealed by the single-sized and multi-sized breeds. I discovered there are seven and their approximate weight doubles from one size to the next as explained further below.

The Great Dane (pictured left), Labrador Retrievers and American Cocker Spaniel (pictured below) are examples of single-sized breeds. The Sleeve Poodle, Teacup Shin Tzu and Miniature Schnauzer, also shown further down, are examples of multi-sized breeds.

I call the seven biological sizes of the dog the sleeve, teacup, toy, miniature, medium, large and giant. I write these names in italics and do not normally capitalize them. I do the same with the word size to emphasize I am referring to the biological size variety of the species.

In contrast, the names of the size varieties of the multi-sized breeds are always capitalized by the dog fancy. For instance, there was a Sleeve Chinese Ch’in and there are now Teacup Chihuahuas, Miniature Pinchers, Medium Poodles and Giant Schnauzers. The Large Poodle is actually called the Standard Poodle. The Medium Poodle is recognized in France where it is called the Moyen Poodle. The Giant Schnauzer actually is a large, not a true giant. like the Great Dane and the Saint Bernard.

Further down is also a picture of a Pekinese. There were four sizes of the Pekinese in China more than a thousand years ago. They were the dogs of the Imperial Court and the four size varieties of the ancient breed are now sometimes referred to as the Chinese Imperial Ch’in to emphasize their history.

How many of these four biological size varieties of the Ch’in still exist today is a good question. The smallest of the four biological sizes usually weighed between 1 and 2 1/2 pounds. They were carried around in the voluminous sleeves of the aristocrats who loved them, so they were referred to as the sleeve size.

Labrador Retreiver
Labrador Retreiver
American Cocker Spaniel
American Cocker Spaniel

Several U.S. breeders now produce Sleeve Poodles, such as Janet Bordelon of Velvet Touch Kennel in Alexandria, Louisiana and Tony Dougia of Dougia’s Cajun Kennel in Walker, Louisiana. The picture of the Sleeve Poodle below is one of Janet’s and we are using it with her expressed permission. While Tony told me there are other breeders who produce this size, Janet and Tony are the only two I am aware of at this time.

If your website shows that you can consistently produce Sleeve Poodles, please email us at and we will add your link to our Teacup Breeders page. The Schexnayder Foundation would like to develop a list of true Sleeve Poodles breeders to use to try to establish a Sleeve and Teacup Poodle Club of America. Establishing such an organization with a membership of responsible breeders who have the right genetics and understand how to produce healthy sleeve and the teacup size Poodles will demonstrate to the scientific community as well as the main stream dog media that the evidence presented here means that my macrogene theory represents biological reality. If you can consistently produce sleeves in any other breed, we would like to know that also.

On our Teacup Health page, we offer recommendations on how to breed healthy small dogs. If you are a breeder or owner, we invite you to share your feedback on a subredit which we will be setting up shortly. We will add the link here once it is ready. This way each breeder can determine for themselves what practices work best and which ones do not. We will use this information to make any modifications we think are necessary on the Teacup Health page. I am not a dog breeder, so it will be up to you and your customers to make these determinations. I am a retired businessman in Houston, Texas and an amateur theoretical bio-mathematician. Learn about me »

Ancient Titian monks produced a breed that is now called the Lhasa Apso, which they used as watchdogs for their temples. This breed today weighs 12 to 18 pounds, making it a miniature, which is a reasonable size for an outdoor watchdog that does not require a lot of food. Gifts of these dogs were sometimes made to the Chinese Impurer. Naturally, as dogs are prone to do, some of these mated with the Ch’in. This resulted in a breed that is now sometimes referred to as the Chinese Temple Dog as well as Shih Tzus. The same four sizes of the Temple Dog were produced as they were is the Imperial Ch’in breed.

The Shih Tzu’s breed standard of the American Kennel Club (AKC) calls for a miniature size dog weighing 9 to 16 pounds. However, some breeders including Mr. Dougia produce smaller size Shih Tzus. Tony bred this Shih Tzu which we feature it with his expressed permission. These smaller size varieties not described in the AKC breed standard are said to be “unrecognized,” although they exist as a biological size variety.

Sleeve Poodle. Courtesy of Janet Bordelon of Velvet Touch Kennel
Sleeve Poodle photo courtesy of Janet Bordelon of Velvet Touch Kennel.

The Six Size Varieties of the Poodle

As I mention above, Ms. Bordelon and Mr. Dougia produce the AKC-unrecognized Sleeve and Teacup size variety of the Poodle. If we take these two unrecognized size varieties and add to the list the three sizes the AKC does recognize—the Toy, the Miniature and the Standard—as well as the Moyen (or Medium) size, which the French recognize, we now have the six varieties of the Poodle. The Moyen Poodle is between the AKC’s Miniature and their Standard size variety. This photo shows this missing size in the AKC’s Poodle lineup; the three size varieties featured in this photo are recognized by the Poodle Club of Las Vegas. You can see the size of the Moyen Poodle by visiting the website of this breeder, who is located in Texas. The Moyen Poodle is not produced by crossing a Miniature with at Standard. The important scientific significance of this is made clear below.

If we take the above six sizes of the poodle—recognized or unrecognized by the AKC—and add to the list the giant size (the size of the Great Dane and the Saint Bernard), we now have the seven sizes of the dog.

The Seven Sizes of the Dog


The Chihuahua is the smallest recognized breed in the world; it can weigh 2 1/2 to 5 pounds or a little more. The AKC’s breed standard says Chihuahuas should weigh 6 pounds or less. However, I think what they are really trying to say is less than 7 pounds. Refer to the “5 Health Problems of Bantamized Dogs,” specifically related to the gynecological complications, on my Teacup Health page for a greater understanding as to why. This allows a breeder to use a 6.5 pound dam to potentially produce three healthy pups.

Fully grown dogs who weigh about 3 pounds can sit inside a normal teacup. Many breeders call these Teacup Chihuahuas to distinguish them from larger Chihuahuas, who often weigh up to 12 pounds. Some breeders call the heavier, 12-pound or so dogs Toy Chihuahuas because they cannot enter the Chihuahua show ring. They use this wording to indicate they more or less understand they are a distinct biological size variety from the true teacup Chihuahua. Because of this, I propose different word usage when referring to the two different sizes of the smaller Chihauhas: If you want to emphasize there are two size varieties of the Chihuahua, one of which is AKC-recognized and one that is not, I suggest using the Teacup and Toy terminology. In other words, when referring to the two biological sizes of the Chihuahua, use teacup and toy.

While the AKC only recognizes three size varieties of the Schnauzer—the Miniature, the Standard and the Giant—some breeders produce Toys. Based in Cleveland, Texas, Janice Edwards of Music Maker has been producing Toys for about ten years that I am aware of. She was the only one for a long time that I could find on the Internet that was doing so. She has always impressed me as someone who understands the genetics.

However, there are now quite a few that are claiming that they are producing both Toys and Teacups. and she has apparently been forced to claim that she is also doing so. However, I have seen several Schnauzer breeders’ websites that lead me to believe they are just producing a downsized toy, as opposed to a teacup. If breeders are actually producing a true teacups, then they should be able to show pictures of adults weighing less than 3 pounds, and other breeders who have obtained some of their breeding stock from them should also be producing such small Schnauzers. However, there is no doubt in my mind that some breeders are producing just a true toy Schnauzer and not a true teacup.

About the Table

table_seven_sizes_of_the_dog_homepage_a_400pxThe table to the right and also shown above contains the rule of thumb for the weight range of the sizes as well as the approximate minimum and maximum weight range for producing healthy dogs of each size. For instance, while the Pomeranian’s breed standard says they can weigh 3 to 7 pounds, it also says that 4 to 6 pounds is the preferred size. This is because the knowledgeable breeders on the committee who wrote the standard know those under about 4 pounds will be less healthy than Pomeranians who weigh more than that. The history of the breed as explained on my Macrogenes and the Dog page shows breeders have reduced the Poms’ size as far down as practice. In contrast, there would be no undesirable health effects if certain breeders deliberately try to produce heavier Poms and stay below 14 or so pounds. For a further explanation of this theory, read my page, The Genetics of Size, where I also explain the Pekinese is a toy and can weigh up to 14 pounds. To get more detail on my references to the f counts displayed on the table, once again, visit Macrogenes and the Dog.

The Doubling Hypothesis and the 2.0 Hypothesis

Not only did I discover the average weight doubles from one size of the dog to the next but also that the weight range doubles as indicated in the table. Therefore, while Miniature Schnauzers weigh about 10 to 20 pounds, Standard Schnauzers weigh about 20 to 40 pounds and Giant Schnauzers weigh about 40 to 80 pounds. Actually, the Miniature does closely fit within that range but the Standard and the Giant weigh somewhat more than those ranges. Nevertheless, they do fit the overall pattern.

Nature allows just enough flexibility in the genome of all mammals so that local populations can adjust their average weight to fit the local climate. Therefore, as explained further below, the wolves and coyotes of the U.S. and Canada have done so. The red wolf of the Southeastern U.S. is a large while the grey timber wolves of northern Canada are giants. The coyote of the Southeastern U.S. is a medium. I do not know if there are any large coyotes in Canada. However, if there are coyotes in the Northwest Territory, they are probably larges.

Whether a mammal is a pygmy shrew, a 10-gram mouse, a hamster, a 3-pound Chihuahua, a 20-pound macaque monkey, white-tailed deer, 140-pound Saint Bernard, Shetland Pony, bottlenose dolphin, 2,000-pound Clydesdale horse, Asian elephant or a 200-ton blue whale, the ratio of the heavier to the lighter members of a natural local interbreeding population will be around 2.0. The key phrase in the last sentence is “natural local interbreeding population.” The distinction will be made clear in the discussion of the wolf below where there are two sizes as also mentioned above. There are also two sizes of rhesus macaque. Therefore, if you look at an interbreeding population with two adjacent sizes, like in the rhesus macaque monkey and North American wolf, the ratio of the heaviest divided by the lightest should be around 4.0.

Macrogene Theory

There are two sizes of rhesus macaques at the Caribbean Primate Research Center, a nature preserve stocked with these monkeys for scientific research purposed from various parts of their natural habitat. Dean Falk studied them. She is an expert on the brains of primates and co-editor of “The evolution of neocortex in primates.” She wrote Chapter 5 in it. On one of her graphs, she shows the weight of macaques at that particular nature preserve ranges from about 5 to about 27 pounds, meaning there should be two sizes at the facility equivalent to the toy and miniature sizes of the dog. This is significant because the macaque genome is sequenced just like that of the dog, house mouse, and human. While the f count of the mouse has been determined, neither that of the two sizes of the macaque nor the seven sizes of the dog has been. If their f counts turn out to be what I predict they should be in the table, this will prove my theory. The f count macrogene is discussed below as well as on the Macrogenes and the Dog page.

In Chapter 2 of the book referenced above, Pasko Rakic and David Kornack discuss the macaque’s brain. They experimentally determined that the variable I call the s count of the macaque is 28 or greater. Other neuroscientists have experimentally determined that the s count of the CD-1 outbred mouse strain is exactly 11. There are several businesses that breed various types of mice that scientists use in their experimental. The CD-1 strain is one of the most popular. I have shown in a scientific paper that different mice strains have a few different s counts.

Please excuse me while I explain a little neuroscience that is summarized in that chapter. Please do not try to read that chapter. I understood very little of it the first time I read it. Anyway, there are two phases of growth in embryos in a part of the brain of mammals called the cerebral cortex. The theory explained in the chapter says that there are a fixed number of cellular division cycles during each of its two phases. They do not explain how this is done genetically, but I knew the answer before I read the chapter. Let me explain.

Although neuroscientists have investigated the the f count, they may not ever be able to experimentally determine the two f tounts of the macaque or the seven of dog by studying embryos. It is practically impossible to do. Nevertheless, when the geneticists locate the gene that determines the f count on its particular chromosome of the dog or the macaque they will be able to experimentally determine the f count to see whether my predictions in the above table are true or no. It will either prove or disprove my theory.

I knew virtually nothing about dog breeds around 2002 when I began this investigation to find the doubling pattern in the dog, although I had not foreseen the 2.0 rule. I knew a lot about the Neadertals. After studying the above book edited by Dean Falk and Kathleen Gibson, I formulated the doubling hypothesis.

I had been studying the Neadertals for about five years at the library at Rice University in early 1998 when I found this article by Michael Hofman on basal metabolism. I found another article that same day. I was able to figure out using those two articles that basal metabolism in all mammals is regulated by the few genes left on the mitochondrial DNA strand. After further study at the Rice library, which included the basal metabolic rates of the smallest rodents to the largest mammals in the database, it was intuitively obvious that mitochondria genes regulates basal metabolism in all mammals including the Neadertals. There are only 37 genes left on the human mitochondrial strand. Encephalization or relative brain size affects basal metabolism as is well known and covered by Dr. Hofman in that article.

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While I was up-to-date 15 years ago on Aiello and Wheeler’s expensive tissue, Martin’s maternal energy and Faulk’s radiator theory, I have not kept up with the latest research concerning these three known restraints on the recent evolution of the human brain. It will take extensive research to produce and publish papers at PeerJ concerning changes required on mitochrondial and Y chromosome genes due to increases in encephalization first occurring in ancestors of sub-Saharan Africans who left no trace in fossil records because of the wet climate in which they lived. Likewise, an explanation of why changes in the unique blood circulation system that cools our brains evolved virtually exclusively in our Neandertal ancestors is needed. These changes occurred as s counts successively increased from about 32 for the Homo erectus population represented in the fossil record while different populations today—depending on their average weight as indicated in my scientific paper—probably have the s counts of 35, 36, 37 and 38.

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Think of the s count like shoe size. The CD-1 strain has been experimentally determined to have a relative size 11 brain, but according to Michael Hofman’s theory, an interbreeding population of mice like that strain cannot have an 11 1/2 size brain, while I can wear either a size 11 and 1/2 or size 12 shoe. Only integer values relative brains sizes are biologically possible according to Dr. Hofman’s theory., which he published in 1982. Relative brain size is called encephalization. The encephalization data in the other article I found that day proved to my satisfaction that he was correct that relative brain size is biologically limited to integer values. It seemed intuitively obvious to my mathematical mind based on those two articles that relative brain size has to be genetically determined by a repeated DNA sequence.

So, after I studied what I could understand in that Chapter 2, it was intuitively obvious that relative brain size is determined by the number of cellular division cycles during the second phase of growth in the embryos in the cerebral cortex of mammals Not long after figuring that out, I was able to mathematically deduce that weight in mammals is determined by the number of division cycles during the first phase. Again, it is like shoe size. Therefore, I call the number of cycles in the first and second phases the f and the s count. I call the theoretical genes that have the repeated DNA sequences that determine these integer valued quantitative traits of weight and relative brain size the f and the s count macrogenes. Therefore, this theory can be proven or disproven by hunting for genes that have repeated DNA sequences where the number of sequences correlates with what I predict in the above table and in the tables in my scientific paper. Actually, I think the f count macrogene has already been found. The number of repeated sequences has been determined in humans and mice, but not yet is dogs and macaques. This actual gene is further discussed on the Macrogenes and the Dog page.

I contacted Dr. Hofman around 2000 once I had figured out what I could based on the two article and whatever else i could find at the Rice library. He snail mailed me an advance copy of his article that is Chapter 6 in the above book. That article is not relevant to dogs or mice. However, after the book came out, I found a copy at the Houston Academy of Medicines, Texas Medical Center Library. which is three blocks from the Rice library. So, I sat down at a table and started plowing through Chapters 1 and 2 trying to see what I could understand until I got to page 39 where it says in my terminology that the s counts of mice is 11 and masques is at least 28,

However, I demonstration in my scientific paper that the neuroscientists who claim that the s count of mice is 11 have probably made a mistake. They only tested the CD-1 outbred strain and everybody assumes that, if it is true for that strain, it is true for all mice strains.

You can see this for yourself in this PDF copy of the paper. The first sentence in the first paragraph in the column on the right says that the s count of mice is 11. Take my word for it. However, the second to last paragraph in the left column says that they only did the experiment on the CD-1 strain. Again, take my word that that is what wording actually means in this context. However, I certainly did not figure that out the first time I tried to read that article

I found Chapter 2 of Rachelle Strom’s Ph.D dissertation using Google around 2005. I use her findings and her data to show that she has probably found evidence for the existence of the s count macrogene that will help locate it. I use her body and brain weight data and Hofman;’s theory to show in my scientific paper that the SM/J inbred strain may have an s count of 12 and the LG/J strain’s may be 7. I use at least one other inbred strain using her data to show that every other number in between is probably found in mice. Outbred mice strains like CD-1 are supposed to be genetically diverse, while inbred strains have been selected over decades to be as genetically identical as possible. Evidently, the CD-1 strain is not as diverse as widely assumed.

She and her colleagues including Dr. Robert Williams at the University of Tennessee Health Science Center where she obtained her Ph.D have the know how to find the actual s count macrogene using my finding of how many repeated sequences should be on the genes of the various mice strains. This is in addition to the main finding in her dissertation that implies that Dr. Hofman’s theory that brain size is sort of like shoe size.

The Doubling Hypothesis and the Dog

In the case of the dog, the total weight range is around 200. Heavy size varieties of the giant size like the Mastiff and the Saint Bernard can weigh 200 pounds or even more, while light sleeve Poodles can weigh around 1.0 pound. Therefore, when we divide 200 by 1.0, we get 200.

The breed standards of almost every multi-sized breed distinguish the size varieties by height. Therefore, all references I could find that provide weight ranges on many breeds sometimes provide obsolete data in pounds, which contradict other sources with the more recent, correct data, or they provide “guestimates.” Therefore, I initially found the doubling pattern and the 2.0 value for all size varieties of the dog by eventually studying the weight range of about 50 single-sized and multi-sized breeds using eight reference books. You can view this data in this Excel spreadsheet or print this PDF version of it.

I used log-base 2 calculations in the spreadsheet to help identify the doubling pattern. You can view the intermediate log-base 2 calculations the spreadsheet as well as the log-base 2 results. Only the log base 2 results can be seen in the PDF. In addition, I list the authors of the eight reference at the top of each of the eight columns of the original data. These are standard references on the dog and you should be able to find several of them in a well-stocked public library or bookstore.

I knew within an hour of the first day when I started my research at the Central Library of the Houston Public Library that I had found what I was looking for when I looked at the first reference book, I found we could clearly distinguish the different size varieties of the multi-sized breeds from the single-sized breeds based on name alone and that the data in each individual source fits the doubling hypothesis in general.

There were a few obvious problems because some sources have obsolete Poodle data in particular because of its unique history with major historical errors conveyed through its official AKC history, primarily due to the lack of understanding of the biology of size on the part of those who wrote it. The Bull Terrier data also has problems because its official history indicates there were once four sizes; the Toy is no longer produced, and the Medium was never recognized. Therefore, only two of the size varieties are now recognized. Thus, several of eight sources have incorrect data on the Poodle and the Miniature Bull Terrier as can be seen in this PDF. However, I distinctly remember learning in De Prisco’s and Johnson’s Toy English Spaniel entry there are three different sizes in its breed family: toys, cockers and springers.

As shown in the PDF, the English Toy Spaniel and the Cavalier King Charles Spaniel are the same size; as are the American and English Cocker Spaniels. Although I did not include this information in the spreadsheet, the Welsh Springer Spaniel is the same size as the English Springer. I subsequently found from their history that the Affenpincher is known to be a smaller size than the Miniature Schnauzer. I was able to determine from the combined history of the Greyhound, Scottish Deerhound and Irish Wolfhound that the Deerhound is the same size as the Greyhound and that the Wolfhound is a larger size. It is a very well known fact that the Labrador Retriever and the Newfoundland are different sizes. I remember the second to last piece of the puzzle I found was in Wilcox’s and Walkowicz’s Toy Poodle entry where they mention the Teacup Poodle. The last piece of information that I found was that there is also a Teacup Chihuahua. That is how I discovered there are six sizes among the breeds recognized by the AKC. Since Michelle Welton says that there is a Teacup Chihuahua, that is good enough for me. She should know.

Michell Welton and Carolyn Coile are the only two that got both the Toy and Miniature Poodle right as seen, but they were both wrong on the Miniature Bull Terrier. Bear and Duno are the only one of the eight that got it right. You can see how I had trouble trying to figure out who had completely reliable data. No one does.

The Poodle and American Water Spaniel data from the eight sources is shown below. The Water Spaniel is included because it is used to hunt ducks like the original size variety of the Poodle. The fact that this duck hunting breed is not the same size as the Standard Poodle was the first inkling I had that the Moyen Poodle was the original duck hunting type. As you can see, some experts were so confined about the proper weight range of the Toy and Miniature that they did not give data on either of these popular size varieties.

Ron Lewis: In this book the authors give the 45-58 height for Standard Poodle, not Medium. Ron Lewis: In this book the authors give the 35-45 height for Giant Poodle, not Standard.
Highlighted in yellow: In this book the authors give the 45-58 height for Standard Poodle, not Medium, and the 35-45 height for Giant Poodle, not Standard.

Michelle Welton in her book, “Your Pruebred Puppy,” categorized each of 200 size varieties into five size classes. We agree on almost all of them. One of those she missed is the Chihuahua where she should have classified it in a sixth class. Chris Walkowicz, in her book “Choosing a Dog for Dummies,” also lists five classes. We agree on most of them but Ms. Welton’s research is more reflective of the conclusions I present. Still, neither one of these dog experts identify the pattern based on history. Michelle devotes one page to each single- and multi-sized variety and Chris devotes either one or two pages. They apparently each worked it out for themselves based on the data they used for the multi-sized breeds and their personal knowledge based on years of study of actual dogs.

I initially identified the rule of thumb in the table below in the data of the American Eskimo Dog. The Eskie is misnamed. They were initially imported to the U.S. by 19th Century German immigrants so they are not related to the sled dogs of native Alaskans. One breeder started using the name during World War I when the U.S. was at war with Germany and everything German was shunned. The name stuck.

Only five of the eight sources provide the data on the Eskie including Welton, Coile, and Bear and Duno as shown below. All five agree very closely on all three size varieties. They all certainly agree much better than in any other multiplexed breed. It was obvious to my mathematical mind when I studied the data in the spreadsheet—when I was looking specifically for the doubling pattern—that the best combined description of the Eskie data is 5–10, 10–20 and 20–40 pounds. After working out this doubling pattern, it became easier to piece together the size history of the various breeds families such as the greyhounds and collies as shown in the three-page spreadsheet.


The Logarithmic Distribution and the 2.0 Rule

The body mass (weight) of local interbreeding populations of animals are logarithmically distributed. This is the theoretical reason why the 2.0 rule is valid. The Eskie data from the table above, the 2.0 rule, and the fact weight is logarithmically distributed, were used to construct the graph above. Falconer and Mackay argue in Chapter 17 of the 4th edition of “Quantitative Genetics” that body mass is logarithmically distributed. Now, they will need to rewrite this chapter based on findings reported on this website. I recommend they now say the body mass of local breeding populations are logarithmically distributed and the proper scale for studying body mass in all animals with radial and bilateral symmetry is log-base 2. These are the animals that have an f count macrogene.

The logarithmic distribution is a case of the bell curve of statistics. See an example. That is why the distance form 5 to 10 pounds in the above graph is the same length as the distance from 10 to 20 pounds as well as the distance form 20 to 40 pounds.

I subsequently found the 2.0 rule holds for various interbreeding size population of the house mouse. John MacArthur demonstrated this in his 1948 interim report on a famous experiment that is now available as this PDF. The experiment eventually took about three decades to complete. Based on a Google search, this paper has been cited in 113 other papers; I found it while reading the above textbook by Falconer and Mackay. In his experiment, MacArthur proves beyond a reasonable doubt there was only one size of the house mouse in the sample with which he started. Three other research teams also confirm this conclusion in other multi-decade experiments to my satisfaction.

There is also only one size of humans. Otherwise, the Phoneticians and the Egyptians would have known otherwise about 3,000 years ago. The lightest human populations live in the tropical rainforest of Africa and Southeast Asia, while the heaviest live around the Arctic Circle in Northern Russia, Scandinavia, Canada and Alaska. The seafaring Phonetician would certainly have known if there were two sizes of humans.

The fact that the different populations of the house mouse through the various 21 generations during the initial part of MacArthur’s experiment were slightly larger than 2.0 is shown in his Figure 4. Since he states the average sample size over the 21 generations was 336 mice, the slightly larger ratio than 2.0 shown on his graphs covers about 2 1/2 standard deviations. Since the weight ranges generally shown for whales and other large animals on various websites are generally less than 2.0, this appears to be a general rule for all mammals as explained above.

The rule of 5-10, 10-20 and 20-40 pounds for the three size varieties of the Eskie, which I found in the table below, is consistent with that rule of thumb. The doubling pattern of the Eskie data and the fact that weight is one of the variables in nature that is normally distributed allows the population structure of the breed to be depicted graphically. The graph of the normal distribution is known as the bell curve, an important mathematical concept taught in high school algebra II and trigonometry.
The population structure of the three sizes of the Eskie is given again below.



I have never read anything that indicates any other scientist has ever investigated this question of the relative size of a local interbreeding population much less actually identified the doubling hypothesis. Actually the fact that all such local populations have about a 2.0 ratio explains why nature evolved the f count macrogene. which is discussed below. Falconer’s and Mackay’s hypothesis that body mass in animals is logarithmically distributed, the 2.0 rule, and the doubling pattern in the seven sizes as I list in this table, which was found in the Eskie data, allows me to present the graph below for the population structure of the dog. Notice there is little overlap in the tails in each of the places where overlap exists. This is the result of the 2.0 rule. I further discuss the Eskie’s history on The Genetics of Size page in my discussion of the inheritance characteristics of the f count macrogene. More on this macrogene below.


The f count Macrogene

There is one master gene containing a set of repeated DNA sequences that determines the size of the dog; I call the total number of these repeated sequences on this gene the f count. A mutation that adds one repeat count to this gene when the egg of a Toy Poodle is fertilized by the sperm of another Toy Poodle can result in the birth of a Miniature Poodle, even if both parents are genetically toy Poodles. This is a very rare occurrence and may never have happened in the 100 or so years breeders have produced true toy Poodles.

According to Desmond Morris in his excellent dictionary of dog breeds, the Toy Poodle was first recognized circa 1900. The so-called Toy Poodles prior to that time were actually Miniature Poodles. According to Morris, the name of the Miniature was corrected around 1900 when the true biological toy Poodle was first recognized. However, even in light of this new evidence uncovered by Morris, the AKC did not correct this detail in their section on Poodle history in the AKC’s “The Complete Dog Book: 20th Edition” (2006). This error in the official history compounded with the problem with the Miniature Bull Terrier data in some of the sources is what led me to include data from the eight books in the spreadsheet. I stopped at eight books because I could not find another one with data on many of the breeds I investigated.

Adding such a repeat count to that gene according to my macrogene theory will cause every cell to divide one more time during growth and thus double the number of cells in the adult body then subsequently double the average weight of a population, which I indicate in the table.

Cerebral cortex.
Cerebral Cortex

I found evidence for this gene when this book,“Evolutionary Anatomy of the Primate Cerebral Cortex,” was published in 2001. Chapter 2 contains the critical information. Pasko Rakic, MD, PhD, ScD at Yale and David Kornack, PhD at the University of Rochester, School of Medicine wrote the chapter. I was able to conclude from that chapter, based on what I knew at the time, that two such genes determine the numbers of cellular division cycles during the first and second phases of neuron production in the cerebral cortex.

Therefore, I have named these two variables the f count and the s count and the two theoretical genes I have named the f count and the s count macrogenes so that it is easy to remember which is which. The f is for the first and the s is for the second phase. Read more information on this gene on our Macrogenes and the Dog page. It just seemed intuitively obvious to me as a mathematician who understands the Peano Axioms that repeated sequences had to be involved baaed on all that I knew then. I discuss only some of what I knew then in this PDF version of a PeerJ PrePrint where I try to demonstrate that the repeated sequence on the s count macrogene determines relative brain size, or encephalization, in mammals.

Evolutionary Changes in Size

As can be seen in the table above where the minimum and maximum ranges for each size are given, there is considerable overlap between the sizes. This overlap is demonstrated below in the graph of the logarithmic distribution of the body mass of three toy size varieties. The data on the Pomeranian and Pekinese that is the basis for the graph is discussed on the Genetics of Size Page. The Toy Eskie data is discussed above.


This overlap is precisely what is required to allow evolutionary changes in size to occur in any animal. The average weight of a successful tropical species expanding its geographical niche into the temperate zone will increase as it moves closer and closer to the North or South Pole. As the weight increases in the local population over geological time, to the point of where it reaches the maximum value for its size as indicated in the table, unhealthy animals will begin to be produced. Keep in mind lighter populations in warmer climates will keep their smaller, lighter-weight physiques. Technically, this is a result of the “first law of thermodynamics.” This tendency of weight to vary with temperature among warm-blooded animals is known as Bergmann’s Rule.

Information in breed standards of the dog indicates they will tend to become muscle bound and they will not be able to run as fast as or have the agility of lighter dogs when they reach the maximum limit, as noted in the table, for their size. The Scottish Deerhound’s breed standard is one of the best examples of this. That is one of the places where I first became aware of the phenomenon. The Giant Schnauzer’s breed standard was the first that I found but it is not as clear as the Deerhound’s. There are many others.

This information in the Deerhound’s breed standard and its widely known history are the reasons why I determined it is the same size as the Greyhound. The widely known related history of the Irish Wolfhound is why I determined they are two different sizes as shown on the spreadsheet. The combined evidence tells us that the maximum weight for a male Deerhound that can hunt like the lighter ones is around 110 pounds; whereas, the original hounds that caused the extinction of the wolf in Scotland that were also used to hunt deer were the size of the Wolfhound. Read any book that covers the history of the two breeds and see what I mean.

Thus, a mutation producing the next large size will be selected over geological time as also can be seen by studying the table. Please notice this will occur no matter which size the local population is. This is why nature has made sure the genome of animals is structured in such a way that local breeding populations have a ratio of about 2.0 between the heaviest and lightest members. The larger repeat count will increase in frequency as the population extends its geographic range further towards the geographic pole. Eventually the heavier population nearest the pole will all be the same, larger size. The geographic hybrid zone where the two sizes exist will shrink in extent. Therefore, there are tiny pygmy shrews with half the weight of regular shrews, miniature hamsters and heavier size varieties of hamsters, Giant Schnauzers as well as Miniature and Standard Schnauzers and pygmy wright and sperm whales as well as regular-sized wright and sperm whales. The ratio of the lightest to the heaviest members of breeding populations of these size varieties are all around 2.0.

Dogs, Coyotes, and Wolves

This is exactly the recent population structure of the wolf and coyote of North America but how it came into existence is for paleontologists to determine. Coyotes, wolves and dogs have the same number of chromosomes and about the same length of gestation period, so they can and have occasionally interbred. However, fortunately, they do not normally do so. Nevertheless, it is a model for understanding how evolution worked in this case.

The coyotes of Arizona and Southern California are mediums like the Cocker Spaniel. Their historic range was somewhat limited to dry areas of the Southwest U.S. and Great Plains into Canada. The red wolf of the Southeastern U.S. is a large like the Labrador Retriever while the timber wolves of northwestern Canada and Alaska (see below) are giants like the Great Dane. The red wolf has been hunted to near extinction. This has allowed the coyote, which is much better able to live in harmony with humans, to move east.

Therefore, at some local particular place in the geographic ranges of the coyote, red wolf, and grey wolf prior to the settlement of North America by Europeans, each one of these should have fit the rule of thumb of 20 to 440, 40 to 80, and 80 to 160 pounds for the dog. The local population to the south would have been lighter and that to the north would have been heavier. The combined structure of these three ideal populations can be depicted by the three bell curves on the logarithmic graph below.


Coyotes now live in all parts of Houston, Texas where they roam along the natural areas along our bayous, the high voltage electricity transmission easements and any remaining natural areas including the large natural areas in our many larger parks. They are frequently seen in these areas and known to sometimes prey on cats.


The Miniature Schnauzer is an example of a size variety of a multi-sized breed. There is also a recognized Standard and a Giant Schnauzer size variety. A recognized breed has a breed club like the American Miniature Schnauzer Club, which has a written breed standard to describe the ideal members of the breed.

Miniature Schnauzer
Miniature Schnauzer

An umbrella organization like the AKC and the United Kennel Club in the U.S. will keep their stud books where all members of the breed are registered so they can compete in sanctioned events. The breed standard of a multi-sized breed defines the multiple size varieties. They almost always use height ranges to define them, although the AKC’s Toy and Standard Manchester Terriers are defined by weight. There is little or no overlap between the sizes however it is done, so almost every dog can be easily categorized as only one size by knowledgeable fanciers.

The Giant Schnauzer is a large: It is not a true giant. The Great Dane is similar to what a smooth-coated, giant Schnauzer would look like.

There is also an unrecognized Toy. The Toys are entered in the stud book of the Miniature. However, as things stand now they are too small to win in the show ring. If the Toy is ever recognized by any breed club, the ones that meet the smaller size specifications would be eligible to be transferred to the new stud book and compete in its own show ring. If this ever happens, it is likely that this new Toy Schnauzer would not immediately be recognized by the AKC, although it probably would eventually be recognized. Each of the three recognized size varieties in the case of the Schnauzer has its own breed standard. One of the reasons for this unusual feature of this multi-sized breed is because the Miniature is in the AKC’s Terrier Group while the other two size varieties are not.

The Standard Schnauzer was an all-around German farm dog and sheep herder. The Miniature was subsequently produced by crossing the larger, now extinct, size variety of the Affenpincher with the Standard Schnauzer to produce a terrier. Terriers have the instinct to enter the burrows of vermin to rid human habitations and barns of rats and mice as well as other undesirable mammals like badgers and otters. The Giant Schnauzers were developed around Muick, Germany in the 15th Century. This may have been achieved by crossing a large rough-coated member of the collie family with a Great Dane. They were used to drive cattle to market. They are now bred for police work.



As explained above, the Chinese evebtually bred four sizes of the Imperial Ch’in and Temple Dog. The Pekinese breed of today, pictured right, is really the third-to-smallest size variety of these four size varieties. The Pekinese, as bred today, can weigh up to 14 pounds. They are slightly heavier than most toy size breeds. Pekinese bred to the breed standard should range from 7–14 pounds.The height and weight ranges of the four size varieties of the Imperial Ch’in and the Temple Dog are given in Simon & Schuster’s “Guide to Dogs” by Gino Pugnetti. This is one of the eight books I used to construct the spreadsheet I mention earlier and the only place I have found that has the ancient Chinese information. The data is presented in the table below. This is a small compact paperback that is ideal to put in a suitcase when you are traveling the world and want to take along pictures to identify the dogs you see on your trip.

The Chinese Temple Dog is now called the Shih Tzu. The miniature is the recognized size. Some breeders are now producing a smaller size variety, which they call the Teacup. They can weigh 2 to 5 pounds, which indicates that they are, in fact, a teacup In contrast, its breed standard call for a range of 9 to 16 pounds. However, some breeders have downsized the miniature. They are producing dogs in the 7 to 8 pound range, which can be done with a miniature, but it remains a miniature, and not a teacup. The 8 pound miniatures can be healthy, but the 7 ponders are usually not. They will have thin fragile bones and other problems. See our Teacup Health page for information on this fragile bones. They occur in any size when breeders try to downsize any particular size variety too far. That will also occur in any domestic breed of mammal, bird, or fish, i.e. any species of vertebrae.

This is an example of an AKC breed club not understanding the history of its own breed. The American Shih Tzu Club has an official statement on this matter. They use a broad brush calling all such breeders unethical.

Tony Dougia of Walker, Louisiana is an ethical breeder of Teacup Shih Tzu as he claims on his website. All such ethical breeders will gladly let you inspect their kennel and their breeding stock. I highly recommend your reading Tony’s one-year guarantee.

It just happens that the two non-adjacent size varieties of the Shih Tzu provides a means of testing my theory, and Tony Dougia could do the experiment if he has or acquires a standard size dam and mates ti with a teacup sire. I bet he is going to just get miniatures and teacups, and not toys. If you are dumb enough to bet against me, you are a sucker because I already know the answer without having the experiment preformed previously.

The experiment has been done in the Toy and Standard Poodle and in the Shetland Sheepdog and the Collie. In the Poodle case, you do not get the Moyen Poodles,:you get Miniatures and Standards. The exception to this rule was done by Crabapple Poodles of Colebrook New Hampshire, but they cheated. They say that they used a large Miniature and a small Standard. One or the other, or both, was undoubtedly a medium. In the case of the two collies, you do not get a collie the size of a Border Collie. The experiment that was cone is described by Wilcox and Walkowicz is what I think is the best dog book ever written, “The Atlas of Dog Breeds,” one of the eight reference books mentioned above.

The Sheltie evolve on the Shetland Islands to tend the miniature sheep that also evolved there. The sheep were later replaced by the more standard size ones from Scotland, so the dogs that tend the sheep now are also larger. Since the Collies that evolved to drive cattle to market were replaces by trucks, the Sheltie and Collie were both subsequently bred to make good pets. However, the Border Collies are still prized by shepherds, which means they can make a terrible pet. They are rambunctious. They were bred to love to heard sheep. If you cannot keep them busy enough with things they like to do, they may start herding your kids. Collies were crossed with Shelties to make them look more like what we think of a Collie should look like. I have found no evidence that anyone is producing a medium size Collie.

In contrast, the authors of probably every quantitative genetics textbook ever written in English would probably bet me that, if Tony reforms that experiment, probably all of the pups would grow up to weigh 5 to 9 pounds.

The Yorkshire Terrier, as defined in its breed standard, is a toy size breed. The toy Yorkies generally range from 3½ to 7 pounds. However, many Yorkies bred by the best breeders today can weigh as little as 2 pounds; many of these breeders claim they do not understand why. At least that is what Barr and Veling claim in their “Yorkshire Terriers for Dummies.” So you have to consider who their target audience is for making such a statements. This website provides misinformation or incomplete information on Teacup Yorkies. There is such a biological entity as a teacup Yorkie. Barr and Veling imply the best Yorkie breeders claim to not know what some Chinese dog breeders knew more than a thousand years ago. Or, maybe Barr and Veling believe their target audience cannot comprehend what the Chinese knew a thousand years ago. Therefore, I am going to explain what the best Yorkie breeders should already know.

More on Wolves, Coyotes and Jackals

All members of the genus Canis including the wolf, coyote and a few species of jackals can interbreed. All members of the genus including all dogs including the Great Dane have about a 63-day gestation period. Larger Great Danes can whelp as many as 15 or 20 pups. It is a well-known but rarely expressed secret that dams weighing less than 5 pounds often require Cesareans and often whelp only one pup. The wombs of the even smaller one apparently may not have the capacity to grow a pup to term. The ancestors of the dog were not that small. Mutations on the f count macrogene are responsible for the seven sizes of the dog while only the three larger sizes probably exist in natural species in the genus

According to the National Wildlife Federation, males grey wolfs range up to 145 pounds. This means, according to my theory, they are giants somewhat smaller than the Great Dane. According to their page about the red wolf, the females of that species can weigh as little as 45 pounds and the males up to 80 pounds, making them larges the exact same weight as Labrador Retrievers. Therefore, my theory supports the premise of those conservationists who claim the critically endangered red wolf is a different species than the grey wolf and deserves much better protection. Nevertheless, the findings reported here should clarify the genetic difference between the two populations. Technically, they are two size varieties of the genus that have different numbers of repeated sequences on their f count macrogene according to the theory proposed here.

The Difference Between the Red Wolf and the Grey Wolf

Red Wolf. Binomial name: Canis rufus (Audubon & Bachman, 1851)

In “Genetic evidence for a recent origin for the hybridization of red wolves,” Reich and Goldstein conclude the red wolves originated as a result of hybridizations that occurred during the past 12,800 years—probably during the past 2500 years.

European grey wolf in Prague zoo
Grey Wolf Binomial name: Canis lupus
(Linnaeus, 1758)



There are now three recognized species of wolves in North America. Although the larger wolves of northwestern North America giants, there still are large grey wolves around the Great Lakes according to the U.S. Fish and Wildlife Service. Biologists can now understand why the two size varieties of the grey wolf of North America are two species that may still share a hybrid zone for size.

Genetic research suggests the red wolf results from hybridization between coyotes and grey wolves. In “Genetic evidence for a recent origin for the hybridization of red wolves,” Reich and Goldstein call the date of the hybridization “uncertain.” They note in one hypothesis, the grey wolf and coyote came into contact as coyotes increased their geographical range in conjunction with the advance of European settlers and as grey wolves were extirpated from the American south. Whereas, “the red wolves could have originated tens of thousands of years ago as a result of climate and habitat changes that disturbed the ecology of the two parent species.”

Reich and Goldstein say having an upper limit on the hybridization date would help distinguish the two scenarios and compared microsatellite allele length distributions from red wolves, coyotes and grey wolves. Based on their assumptions, they conclude the red wolves originated as a result of hybridizations that occurred during the past 12,800 years—probably during the past 2,500 years.

The Mexican wolf is even more endangered than the red wolf. They were native to the U.S. Southwest competing with the coyote for food. They weigh 60 to 90 pounds. The smaller, medium, coyotes specialized in smaller game while the larger, large, wolves specialized in heavier ungulates, although they would opportunistically prey on smaller animals. The Mexican wolf has been added to the above coyote, red, and grey timber wolf graphic below that now shows four species.

The red wolf did not have to compete with the coyote in its natural habitat. so they could prey on both smaller and larger game while excluding the smaller competitor. Therefore, it could have and probably did adjust its weight range to span the sweet spot for its size. The Mexican wolf din not have that luxury in its habitat, because it could and apparently did increase weight to the range of Scottish Deerhound. The wolves did best at higher elevations This was probably needed to be able to take the larger ungulates,

While there apparently has been a lot of research on the relationship between the red and grey wolves, there does not appear to be any research concerning the relationship between the four different wild species of the genus in North America in with respect to the seven sizes of the dog.

Further Research on Wild Species

If you would like to help me organize a further research project using the existing literature on the wild dogs of the genus Canis …

According to the American Wildlife Foundation, there are three species of African jackal, which weigh from 15 to 35 pounds. This means there is only one size but different interbreeding populations within these three species. As far as I can tell, there is no natural toy or miniature size species in the genus Therefore, according to my theory, the four smaller sizes of the dog evolved by human selection based on the theoretical f count macrogene.

The PDF copy of the initial rough draft of my paper it is available here. It still has several errors in it. I paid American Journal Editors more than $1,200 to edit it and have a pre submission peer review done by three experts. The experts gave me good advice on how to improve it for submission on PeerJ for a formal peer review. However, they edited it in such a way that made me sound like a Ph.D. in experimental biology who dropped Calculus 101 after the third day of classes, failed Chemistry 102 the first time and would not walk past the Physics building. Instead I have a BS in math with a minor in physics and did not take a biology class in college.

Teacups and Toys

Breeders who try to produce dogs smaller than 5 pounds have been doing important scientific research in my opinion and those who know how to do it like Janet Bordelon and Tony Dougia are getting paid well to do something they apparently love to do. However, a breeder has to have the right genetics to produce teacup and sleeve size dogs. A breeder has to understand the complications that can occur if one tries to breed a dam weighing less than 5 pounds.

At least Barr and Veling thought their readers could understand that many Yorkie breeders will not breed their 4-pound Yorkie females but that is one of the few things they got right in this regard. In my opinion, Hungry Minds, Inc. needs to cancel the Yorkie book or at least update it. Maybe they could do a Teacup Size Dog for Dummies book. If they get a competent co-author, I would love to do such a book, if they make it worth my while.

Small Teacup size dog are small enough to sit inside a teacup. Here are some of the other small dogs Tony has bred. The Teacup Yorkshire Terrier pictured above was bred by Janet Bordelon. We are featuring her photo with her expressed permission. See photos and weights of her Yorkie Sires. It appears to me that the 1-pound 10-ounce Harley Davidson is probably a sleeve and not a teacup. She probably knows that.

Because of the trouble reputable Teacup Yorkie breeders like Janet and Tony go through to produce such small dogs, let alone the Sleeves, they can get paid a considerable amount for their whelps. Therefore, the best professional Yorkie breeders who compete in the show ring—and try to get as high a price as they can for some of their dogs that are not show ring quality—appear to me to be jealous of the prices that Janet and Tony can command. Therefore, Barr and Veling claim that people like Tony and Janet are unscrupulous and unethical breeders. Who is the dummy in this case?

Many professional show ring breeders use a practice they euphemistically call “line breeding” to distinguish from outright inbreeding. They will not breed a father to a daughter but they routinely breed a grandfather to a granddaughter and a grandmother to a grandson. This is what it takes for some to professionally compete in the top show rings of today. So if that is the kind of genetically inferior show ring quality dog you want, get it from one of the line-breeders. Otherwise, patronize a breeder committed to producing non-inbred dogs who have good depositions and are socialized to interact with humans. The more quality time a puppy has with humans before you get it the better pet it will be. Good breeders of very small dogs know they have to keep them a few more weeks than is usual for larger size varieties.

However, there are Teacup Yorkie breeders who do not have the right genetics in their breeding stock to produce true genetic teacups. They breed their smallest toy sires to small toy dams and call them Teacups. This inevitably produces unhealthy dogs. Part of the mission of The Schexnayder Foundation is to provide the information on our theory of how to produce healthy small dogs on our future Teacup Size Dog website. I do not own a dog and have absolutely no desire to start breeding dogs. It is my hope that Tony Dougia, working with the Teacup Size Dog website, will use his contacts with the network of reputable breeders he has worked with over the last 10 or so years to help set up breed clubs for small Poodles, Yorkies, and ShiH Tzus. I would also like to set up a Toy Chihuahua breed club.

The Chihuahua Teacup Statement

The Chihuahua Club of America has an official Teacup Statement where they vehemently deny there is such a thing as a Teacup and Toy size variety of their breed. They make this claim on the flimsy grounds that a Teacup and Toy size variety are not defined in their breed standard as if they are the official keeper of the genome of their breed.

Teacup and toy size Chihuahaus.
Teacup and toy size Chihuahaus.

Almost all multi-sized breeds distinguish the size varieties based on height because it is easy for the human eye to easily compare two dogs when they are side by side. The two Chihuahuas pictured right are clearly significantly different in height.

In my opinion, the people responsible for the Teacup Statement are hypocrites. The evidence comes from Clark and Brace’s encyclopedia of the dog. However, Clark and Brace were too intimidated by the Teacup Statement to put the information in their Chihuahua entry, so they put it in their Yorkie entry instead. According to what they wrote using the nomenclature proposed here, some Chihuahua breeders knowingly breed a lighter teacup sire to a heavier toy dam. This means many of their pups are too heavy to compete in the Chihuahua show ring because they can weigh up to 12 pounds. I know this because Welton includes in her book they can weigh 6 to 12 pounds. Chihuahuas 7.0 pounds and heavier cannot compete in the Chihuahua show ring. In my opinion, Welton’s book is the best of its kind and Chris Walkowicz’s “Choosing a Dog for Dummies” is second best. I do not recommend any of the other advice books on choosing a breed.

It’s obvious Clark and Brace imply in their Yorkie entry that this practice by knowledgeable Chihuahua breeders results in the well-known fact, as reported by Welton, of many unknowing buyers winding up with much larger Chihuahuas than they thought they were buying. Therefore, knowledgeable Chihuahua breeders started using Teacup and Toy nomenclature. That said, in my opinion, the people responsible for the Teacup Statement are either dummies, unqualified to make such a statement or intentionally trying to deceive.

Ruth Terry opened Terrymont Kennels in 1957 and is a very successful show ring exhibitor and Chihuahua breeder. On page 90 of her book, she writes: “Many breeders think that show ring stock should also be breeding stock.” She recommends waiting until a pup is six months old before buying show ring or breeding stock. She implies the adult weight of the pup will be known by then.

Who are the dummies? Who understands there is a genetic difference between a Teacup and a Toy? Why were the breed standards of so many multi-sized breeds written in such a way that body mass approximately doubles from one size to the next?

The answers to the second two questions is that the biological sizes of dog are determined by the numbers of repeated DNA sequences on a gene that I call the asp count Macrogene, read about it now »