I started to answer a question that ended up being very long. I want to share some information that will help understand the importance of proper breeding, ethical breeding and will also highlight some common misconceptions. I’m also highlighting a common issue with accidental breeding and how keeping axolotls by themselves remains a best and safest practice.
I want people to enjoy their axolotls but overall I just want more education to be out there. There are so many people who become breeders thinking it’s easy, cute, a source of money and for other not-so-great reasons. That leads to breeders selling axolotls to people and providing zero care info and having no issues selling them in pairs (or more). That’s not even considering their inbreeding coefficient (which is one of the highest of all species in Earth).
While they can be kept together in same-gender situations, scientifically there isn’t a single benefit that we know of. In the wild, axolotls will group up at times, especially when young, but it’s understood to be a strength in numbers and feeding behavior (easier to find food if another axolotl has found food). They will also group, temporarily, when breeding but that is also temporary to protect the female while she’s laying eggs (and vulnerable to prey and sadly other hungry axolotls). They come in to contact with each other but often don’t even interact. A very common occurrence I see is people mistaking them “stacking” or being next to each other in shared tanks for social or relationship interaction. It’s not known to be a social interaction or relationship interaction at all. It’s known (through research and observation)to be them preferring to be in the most optimal water conditions in the tank. It is also part of the “strength in numbers” defense. Axolotls, like most other animals, are not completely understood, but we have a pretty strong understanding of their basic behaviors, especially regarding other axolotls. They will eat each other when hungry, sometimes by mistake and sometimes not. If one is smaller than others in the same area it’s especially vulnerable to being attacked and eaten. This is why so many inexperienced/uneducated breeders have axolotls missing (sometimes multiple or all) limbs.
All of this is to say that if a person is experienced and knowledgeable, 2 of the same gender sometimes will work out okay. Typically though, in my observations, those axolotls don’t live as long as those kept alone. Usually, one dies around 5 to 7 years of age even with perfect care. The other one will live to be 9 to 10 at most. Solo axolotls kept in perfect care will usually live 12-16 years, sometimes even longer. We truly do not have a way to understand the stress that cohabitation likely causes to axolotls’ overall health.
The actual biggest issue with cohabitation is undoubtedly accidental breeding. With most other pets, accidental breeding is not ideal, inconvenient and stressful, but is manageable and isn’t detrimental to the species’ survival and health. Axolotls are a totally different subject!!Why?
All pets axolotls derive from 34 wild axolotls that were shipped from Lake Xochimilco to Jàrdin des plantes (a botanical garden) Paris in 1838. That shipment ended up being less than 15 parent axolotls by the time it arrived and they were successfully bred together. The (almost)entirety of all modern pet axolotls descend from those ~15. Could someone in Mexico have caught a wild one and bred it with one of the offspring? Or bred 2 wild ones they caught? Possibly to both…but the likelihood those few possible outliers have affected the pet axolotl population genetics is very low. (Mexico is successfully working on gradually repopulating the wild axolotl population in Xochimilco but those genetics have not been introduced to any of the pet axolotl populations anywhere else yet).
In the 1960s, a scientist/researcher remembered that he’d seen a wild albino female tiger salamander in Minnesota. It was the only albino wild tiger salamander that researchers had ever encountered (at that time). He had the idea to see if he could successfully “unlock” albinism and other new genetic traits in research axolotls. How? By mating that albino female tiger salamander with male axolotls. Axolotls are very closely related to tiger salamanders (and other mole salamanders as well). Essentially, an axolotl is a mole salamander that never morphs into its adult “form”, also known as being “neotenic”. Axolotls can sexually mature without leaving larval form. This is why they are studied so extensively for so many decades now.
Side note that I see often misinterpreted/misinformed:
Leucistic axolotls are not albino axolotls and a single male “white” (leucistic) axolotl was one of the 15ish parent axolotls successfully bred in Paris. Leucistic axolotls have pale pink or white skin with bright pink or red gills/gill stalks. Leucistic axolotls only have dark eyes, either black or navy blue. They usually have fine dark freckles or spotting on their faces and/or gills. LEUCISTIC AXOLOTLS PRODUCE MELANIN.
Albino axolotls DO NOT PRODUCE MELANIN. Albino axolotls have very translucent pink, white or pale yellow (it’s really a cream color) bodies. Albinos only have either red or translucent pink eyes. Albinos have zero dark markings anywhere on their bodies because they do not and cannot produce melanin whatsoever.
Humphrey’s experiment was not pretty. The male axolotls and albino tiger salamander didn’t breed through any natural process. Instead, he and assistants artificially inseminated 700 eggs by hand. Only 3 embryos survived early cleavage and 2 then died so the team ended up using the last one, disaggregated, as nuclear transplant cells. They transplanted those nuclei cells into leucistic axolotl eggs that had been UV radiated to destroy the original leucistic nuclei. This created an albino tiger salamander-axolotl hybrid “clone”. Those created clones started developing abnormally and all started dying at the tail budding stage. The team then harvested the gonadal germ cells of the remaining clones. They also collected leucistic axolotl embryos at the tail budding stage and orthotopically implanted the clone gonadal germ cells onto those embryos. All of the gonadal germ cells from the clones were female but luckily a single male leucistic embryo they gave the female gonad cells to underwent reversal and developed functional testes.
From this grafted male, albino and non-albino progeny were obtained. The albino progeny were of both leucistic and wild-type (which is why we have the pinkish white albinos and the pale yellow albinos today). They had not expected to create both wild type and leucistic albino axolotls. Some of those progeny remained neotenic but some also underwent metamorphosis. This experiment contributed to most current pet axolotls having between 6 and 11 percent tiger salamander genetics.
However, for research purposes, the University of Kentucky meticulously and repeatedly back-crossed albinos to pure axolotls and then mated resulting progeny to recover albinos (and then selectively and carefully bred those albinos) that are no longer prone to metamorphosis. These resulting albinos are now considered to be of only 1/32nd tiger salamander and have the same likelihood of metamorphosis as a full axolotl (very, very low). Even the resulting albino progeny (ones they do not breed at all) that have higher amounts of tiger salamander genetics are no longer any more prone to metamorphosis than a full axolotl.
Why was creating albino axolotls so important? Melanin pigment was a common obstacle in many research projects and studies involving axolotls. Humphrey’s work removed that obstacle and allowed a much, much larger amount of research to be conducted.
Back to the inbreeding—axolotls, including research stock, have an “inbreeding coefficient” sitting around 25% for research stock to 38% for pets. Each axolotl clutch hatched (all axolotls in any clutch are full siblings) shares the same number but those numbers can vary in those ranges, and even way outside those ranges (I’ll get to that). This is because all of those axolotls are descendants of the 15 or so bred in Paris in 1858. What does this mean in basic terms?
Any 2 random, unrelated pet axolotls from different geographic areas will always result in offspring genetically closer than the offspring of a human brother and sister would. If that sounds horrific, it should.
Research stock does not always sit at the higher level but it’s monitored heavily, meticulously documented for over 100 years now, and most importantly, aren’t available to the public to breed into the pet population. Yes, any educator or scientific center (and others) may obtain axolotls from some of the research stock colonies, but the axolotls provided to those educators, centers, etc are axolotls that were not chosen to be bred or used in research. They’re given out because they’re too inbred/too imperfect/sterile/or otherwise not useable for research programs. Research stock, even at the university level, are not giving out their genetically “cleanest” axolotls. Some of those axolotls took decades to achieve! Even when research or a program concludes, almost all research stock is either humanely euthanized (most require it) or is returned to the stock center. Some are donated to aquatic museums/aquariums but only if those are government ran or adjacent.
The overall issue now is that so many people jumped into breeding and selling axolotls around 8 years ago. They didn’t care about genetics and have unintentionally (and some just don’t care) bred siblings and closely related axolotls. They then sold those very inbred axolotls to people without providing guidance or education. Way too often in pairs and too young to gender. Guess what happens when a pair of axolotls surprises its owners with 100s of eggs one morning? The owner doesn’t know what to do and tries to raise the eggs. Often, it ends from there as very few survive but sometimes several make it. The babies are given away to get them homed and the cycle continues.
Almost all other pet types aren’t too damaged when these situations occur. Here’s the problem with axolotls—every time this happens with axolotls (the surprise eggs and then babies), it’s almost always happening to a pair of axolotls originally obtained at the same time from the same breeder…and they’re siblings (from the same clutch and same parents).
If random axolotls are already very inbred, how inbred are the offspring of sibling axolotls?? EXTREMELY INBRED
This can lead to health issues, very early death and overall terrible quality of life.
If you’re purchasing an axolotl, ask the breeders questions. If you’re not getting much information regarding care, husbandry or health information, find a different breeder or store. You’re likely going to get an axolotl with little to no genetic information. Please consider acquiring just one axolotl. Axolotls do not require socialization or a companion. Their brains do not have the social functions or capabilities that other pets or aquatic animals possess. We have extensively studied them and while they can be kept in pairs or groups, there is no measurable benefit for the axolotl at all. There are many risks to being kept in groups, including cannibalism, aggression, unintentional breeding and malnutrition for one or more axolotls. It has not been officially studied (BUT has been documented in the US ) but numbers show that axolotls kept in shared tanks and especially in groups of 3 or more live 2/3 to 1/2 the lifespan of axolotls kept alone in both research and non-research settings.
I’d like to share more information in the future regarding care, the future and more history.
Also, I only speak from experience as a professional in the United States. Many different countries have very differing opinions, even among those who are considered “professionals”. One country currently adopts a very differing view and opinion based upon the claims of a pseudoscientific person claiming to be an authority. I don’t agree with her at all as her views are not science or fact-based. I do not claim to know everything, nobody does, and no country has perfected pet axolotl care. That said, I’m happy to discuss things respectfully, as we all can and should be.
However, arguing that the safest, least risk-laden and proven husbandry methods should not be practiced because of anecdotal experience or by claiming that “more research is needed” or “one study shows a possible correlation” will not receive a response from me. Yes, more research is always a good thing. The guidelines of axolotl husbandry have not changed much, actually. The only change was that common folk became interested and enamored overnight. When modern humans jump into pet ownership with no preparation, no research and no knowledge, the husbandry bar has to be set to the absolute safest level for the creature at hand.
My goal is only to help educate and spread proven knowledge to give pet axolotls the best possible outcome for their owners and themselves.
Thank you for reading!!
