The Xolo is one of the world’s oldest and rarest breeds. Evidence of their existence has been found in the ruins which remain from the Pre-Columbian societies of Mexico and the countries of Central and South America. Archeologists have collected and identified their remains and done comparative studies between the Xolo and the "common" dogs of Mexico. Identical looking statues dating back 3,000 years, have been found in tombs of the Mayan, Colima and Aztec Indians.



The Xolo were valued for their loyalty, companionship and intelligence as well as their curative and mystical powers. Xolos were used as companions, bed warmers, food and even religious sacrificial offerings. Remains of Xolos have been found in burial sites. The Aztec people held great faith in the ability of the Xolo to guide them to their "land of the dead", or "Mictlan", after their death. For this reason, many were buried with a Xolo, which of course was sacrificed for that purpose. .




The name “Xoloitzcuintli” is derived from the Aztec god “Xolotl” and the Aztec word for dog “Itzcuintli”. At one time Xolos were prevalent throughout Mexico and large portions of South America. After the Spaniards conquered the Aztecs, the breed population dwindled and was kept alive by secluded Indian tribes in remote parts of Mexico and South America. The breed was eventually re-established by the Countess Lascelle de Premio Real and other Mexican breeders. It was first registered in Mexico in 1955 and is now the designated official dog of Mexico.


Because of it's hairlessness, the Xolo feels very warm to the touch. Some people believe that the body temperature of the Xolo is higher than other dog breeds. This is not true. It's body temperature is within the same range as that of other dog breeds. They do surprisingly well in cool weather but often need a sweater when the temperature is very cool or cold. In the winter in the northern hemisphere they are a house dog. The lighter colors may sometimes need protection from the sun. The Xolo skin darkens with exposure to the sun and in the winter they may grow very light if they are kept in the house most of the time. White areas or spots on their skin will continually burn from the sun. The Xolo is a very devoted dog and dislikes being apart from its human owner. They tend to bond primarily to one person but are devoted to the entire family. They make excellent watch dogs and do not bark without reason.




The Xolo ranges in size from very small Chihuahua size to quite large or Doberman size. Standards for the breed vary in the United States and Canada but are the same in all other countries, under FCI rules. The Xolo is a rare breed, numbering approximately 4000 in the world. It is not common, even in Mexico. Members of the Federacion Canofila Mexicana began a registration and breeding program for the Xolo on May 1, 1956. Prior to that time the Xolos were considered nearly extinct.




For the purposes of judging in the conformation ring, dogs are grouped according to their type. At first the Xolo was in the non-sporting group but in 1974 it was listed as a working breed because of it's protective qualities. Mexicans believed that placing the Xolo in the working group would better explain its traditional image. Within the last few years the Xolo was moved to the Spitz and Primitive group, Group 5. Each breed has a "standard" which is a description of what the dog should look like. The Xolo is judged according to the breed standard for it, FCI Standard No. 234, in most countries of the world.  

Opinions vary regarding the value of the 'coated' Xolo in breeding programs. A percentage of the puppies of the Xolo are coated, or have a full covering of hair like other dogs. The hairless gene is dominant in the Xolo. If a breeder consistently breeds hairless to hairless in a breeding program, about ten percent of the puppies will be fully coated with hair. This percentage increases dramatically if coated breeding stock is used and bred to the hairless. If two coated Xolos are bred then the puppies will always be coated, 100 percent, and no hairless will be produced.

For more information, read this by Mexican Breeder Marco Hernandez.




Hello everyone!


When we hear the word mutation, our mind make us think about abnormal, horrible beings. However, although, certainly not in such a spectacular way, mutations form pat of every living being´s normal life, even more, we all are mutants, how can this occur???

DNA is the molecule of heredity. Each time that a being repoduces or a cell multiplies in our tissues, DNA copies are created. This molecule can be described as a code or sequence, represented by letters: G, C, T. A. Every three letters a significant unit appears, thus we could have the following sequence:

GGG-CCC-AAA-TTT hence, when DNA is copied, the ideal thing is to get the same sequence…but reality is that due to many factors such as transcription errors, radiations (even sun radiation), chemical substances….or many others..sometimes instead of getting the same sequence you get a variation. It happens every day, it happens in our bodies, right now, this is happening.

So  that is why a sequence like: GGG-CCC-AAA-TTT can suddenly be transformed into: GGG-CCA-AAA-TTT. This is a mutation.

This small errors in the sequences, (which in reality are huge of thousands and thousands of units, not only four as shown in the example) can be compared with errors in writing. One letter can be exchanged, a period is missing, a coma is missing, order of letters is inverted and so on….Most of the time these small changes are irrelevant (this does not mean that mutation did not occur, though)…but sometimes these changes can produce different meanings in a word, sentence or even whole paragraphs!!! Same thing happens wih DNA mutations..some times the changes are indetectable, sometimes they change details or sometimes they produce great changes in the organisms. In fact every sonle being including us are mutants due to these small changes in our individual DNA. Of course, recombination during reproduction is the way all of this is transmitted through generations. Every organism is a mutant, except clones..and this is the genetical variability of a gene pool.

As said before, some mutations are minimal, other are quite obvious….independently from the magnitude of the changes, some mutations are good and others are adverse to the organism. Here it is that natural selection appears and the result is evoultion. Organisms with good mutations will thrive over those with adverse changes, according to the environmental requirements.



Long ago  somewhere in Mexico, a coated dog, namely an Itzcuintli bitch whelped a number of hairless puppies. This was because of a mutation resulting in ectodermic displasia a condition that produces lack of hair and small incomplete teeth. Regarding nudity, the Xoloitzcuintle is not product of progressive evolution. Instead, a mutation with very notorious effects occurred. It happened suddenly. This event could happen once or many times within the Itzcuintli population. This is because a given population of organism do present some parts of DNA sequence more prone to similar changes.

It has been since then, that due to the specific characteristics of this particular mutation that litters have been mixed (hairless and coated). This is a necessary biological condition and it is unchangeable. Duality in these dogs will always exist. Furthermore, it was the coated dog the one that originated the hairless variation and also, it is the coated the genetically pure form of the breed…hairless xolo is a mutation affecting part of the original coated Itzcuintli population. It is not an essentially different thing. In fact, coateds and hairless, although different in a single mutant gene, share the incredibly huge DNA sequence. Their genes are exactly the same. This also goes for Peruvian Hairless dog an Chinese Crested breeds.

The sudden way this mutation appeared let us to state that some beliefs about Xolo nutrition are essentially incorrect. Some people believe that the Xolo lost their teeth gradually as a result of progressive evoution towards a vegetarian diet. It is highly possible indeed, that Itzcuintlis and Xolos were fed with many vegetal food and that they had to adapt to this diet by selective evolution. Even like this, the lack of teeth in Xolos does not reflect this. Xolos still today are omnivorous canines and they do need animal matter in their diet.

One example that illustrates as possible the sudden mutations event in canines is the documented case of the American Hairless Terrier. Among a regular population of these terriers, one day a hairless litter appeared. Working with these puppies a new breed was established. However it is important to state that this mutation in the Terriers is another, different mutation that the one that the other hairless breed have (Xolos, Peruvian, Chinese Crested). A different part of the DNA sequence mutated creating a similar effect. In fact Hairless terriers have small hairs creating a surface similar to touch to that of a peach, also the Terrier mutation does not affect dentition.
Thanks for reading,


    Please read the text below by Åsa Lindholm.




Hairlessness, an advantage?

It is normal for mammals to have fur. The ongoing evolution is a continuous development which brings change and renewal. A part of the "news" arising from a slow adjustment, others are results of more drastic mutations. The latter is a change in a property that is due to the DNA molecule is not coding for the right protein. It can be done for example by a shift in the reading of DNA "recipe" which gives rise to a new product. The vast majority of mutations is to the detriment of the individual and the nature and disappears quickly from the population, perhaps because the carrier dies in an early stage. A few mutations are of benefit to the individual who carries the mutated gene and causes, under the prevailing conditions and circumstances, benefits.



  Hairless dogs have been known in Central America for several thousand years. Decorated pottery from around the year 1000 BC show images of dogs without fur. When the Spaniards invaded Peru in the 1500s they testified that the hairlessness was common among Indians dogs. The western natural historian and zoologist thought that the naked dogs were  considered to be degenerated drifts.

Let us stop and think about the last claim. Nude Dogs have apparently long existence , which must mean that hairlessness in some way involves an advantage.

The countries where the naked molecules have been spread among the dog population has a favorable environment for all kinds of insects. For dogs to humans are parasites a constant source of discomfort. One theory is that the naked dog had easier to shake off the attacks and didn't  to the same extent as the hairy ones  host such as tick colonies. Recent research has presented the same assumption as a basis for human hairlessness. When we learned to stay warm by other things than our own fur the benefit of being naked was greater than the inconveniences it means to not be hairy.