It’s one of the hobby’s most hot-button topics, and one that elicits spirited and emotional responses from both sides of the argument. For many, the topic of hybridization is a fascinating one, and curious hobbyists hear about hybrids and want to find out more about them. Unfortunately, any public inquiries in the hows, whys, and why nots of a potential mixing of species swiftly erupt into heated arguments and debates.

On the one hand, there are the folks that don’t think tarantula hybrids are that big of a deal, with some even expressing that a keeper can do whatever he wants with his spiders, as long as they aren’t sold into the hobby. Many of these keepers believe that the supposed problem of hybridization in the hobby is over exaggerated and that those who are staunchly opposed to it are alarmists.

Others find the idea of purposely crossing species appalling and unforgivably irresponsible under any circumstance. Many of the people on this side believe that hybrids are prevalent enough in the hobby to seriously compromise the purity of many bloodlines. Any attempt to knowingly breed them is a gross disservice to the hobby and, in some cases, a Frankensteinian perversion of nature.

Recently, I was emailed by a young man who was new to the hobby and eager to discuss some of his experiences with a more seasoned keeper. During our exchange, he mentioned that he had managed to obtain a mature female Brachypelms vagans as well as a mature male Brachypelma albopilosom. He really wanted to breed but was having difficulty acquiring a male for his vagans, so he came up with the idea of trying to crossbreed the two species to get, “a cool designer tarantula.” What ensued was a lengthy back-and-forth email discussion about tarantula hybridization and why it is a detriment to the hobby.

It can be difficult for new and casual hobbyists to understand why hybridization is so frowned upon by many serious hobbyists. Even after several emails, this young man still didn’t seem to fully grasp why this practice was considered taboo by many. As I’ve encountered this question many times myself, I thought it was time to tackle the topic in hopes of educating folks who may not understand why it is such a controversial issue.

Below are the arguments and counter arguments and how they usually break down. For clarity, stances supporting hybridization will be in GREEN; stances against will be in RED.

THE ARGUMENTS

We do it with other animals, like snakes and dogs, so what’s so wrong with it? One of the arguments I hear most is that cross-breeding is done with snakes all of the time, so why would it be wrong to continue this trend with tarantulas? Many tarantula enthusiasts have also spent time with herps, and they are quite accustomed to the rampant and strategic breeding done to increase the chances of getting desirable color morphs. Heck, last I checked, there were over 5,000 ball python morphs. That represents a lot of crossbreeding. The fact is, humans have been strategically crossbreeding animals for years to produce desired traits.

So, if a tarantula breeder wants to mate his female B. boehmei to a B. hamorii male to get a uniquely patterned spider, isn’t that the same thing?

Well, the answer is quite simple, really. No, it’s not. Snake breeders are simply breeding different color and pattern variations of the same species. For the most part (woma/ ball python hybrid aside) no one is currently breeding boa constrictors to corn snakes in order to create a brand new hybridized animal. All of the unique and crazy color patterns are the result of breeding the same animals with different patterns and colorations.

This is the same with dogs as well. When one breeds a poodle to a Labrador retriever to create a Labradoodle, said breeder is in no way crossbreeding species. After all, these two types of dogs are breeds, not different species. They are still both Canus lupus familiaris, and as such, the mixing of the two doesn’t represent a pollution of species DNA.

Many would also be quick to point out that this type of breeding often comes with its own set of consequences. Getting the desirable recessive gene traits to appear often involves inbreeding. This leads to many undesirable health issues in the animals, like the wobble of spider ball pythons and skin and hip problems in dogs.

It’s important for hobbyists to recognize that breeding two different tarantulas together is not at all the same as breeding two ball pythons or dogs. Unfortunately, many people see tarantula species as “breeds” or color forms and not as individual, genetically diverse species that need to be kept separate. It’s better to approach the topic with the mindset that you’re breeding two entirely different animals together.

Hysterocrates gigas/hercules/ederi Hobbyists have long recognized that the hobby bloodlines of genus Hysterocrates have likely been irrevocably polluted due to mislabeling and accidental crossbreedings. For years, gigas, ederi and the fabled Hercules have been mislabeled and crossbred, leading to some to speculate that much of the hobby stock may be hybrids. Sadly, many believe that only wild-caught stock can be considered pure.

But how often does crossbreeding really happen? Many arguments against cross-breed fear-mongering point out that it is probably not nearly prevalent enough to do serious damage to the hobby. When one considers the number of tarantulas sold each day, many of them imports from well-documented captive bred European stock, it seems that an occasional hybrid would only be a drop in a very large bucket. Couple that with the fact that the vast majority of tarantulas purchased are never bred, and it would seem like a very negligible issue. Hobbyists who take this stance don’t necessary condone the practice, but instead take a more neutral stance on it.

The fact is, even a few successful crossbreeding projects could negatively impact the hobby. It’s impossible to summarize just how much the hobby has been polluted by crossbreeding, as much of it occurs accidentally and with no ill intent. Few keepers double-check and cross reference their animals with published species descriptions to ensure that the species they obtained is labeled correctly. There are plenty of instances in the hobby where a keeper is sold what they think is species A only to discover (sometimes accidentally) that they have a different spider. And with spiders yielding clutches of hundreds and even thousands of slings, a few accidental hybridized sacs could have a considerable impact on the hobby.

Let’s say Keeper A has a pure Poecilotheria regalis female that he’s looking to breed. He goes online and finds that another keeper is selling what he believes to be a mature male regalis for breeding purposes. Unfortunately, Keeper B really isn’t that into the hobby and up on his species, and his male regalis is, in fact, a P. formosa. It’s an honest mistake, as they do look similar to the untrained eye.

Keeper A pairs the two, gets a sac, and happily advertises over 100 healthy little P. regalis slings for sale. The majority get picked up by keepers who have no intent of breeding their animals and only want them for display. However, Keeper C gets a couple females of this regalis/formosa cross and decides to breed…

This is how one accidental crossbreeding can have wide-reaching consequences in the hobby. Although many would never know that their supposed Poecilotheria regalis slings are hybrids, that’s the crux of the problem; there’s sometimes no way to tell. These mutt spiders can now enter the hobby and pollute breeding bloodlines, and their impure genes can continue to spread.

A recent report by the U.S. Fish and Wildlife Service on the conservation of genus Poecilotheria had this to say about captive bred stock:

“Individuals in the pet trade descend from wild individuals from unknown locations, have undocumented lineages, come from limited stock (e.g., see Gabriel 2012, p. 18) and are bred without knowledge or consideration of their genetics. They also likely include an unknown number of hybrid individuals resulting from intentional crosses, or unintentional crosses resulting from confusion and difficulty in species taxonomy and identification “(Gabriel 2011a, pp. 25–26; Gabriel et al. 2005, p. 4; Gabriel 2003, pp. 89–90).

Although the extent of the accidental inbreeding is unknown, captive bred Poecilotheria DNA is already considered too potentially polluted to be useful in restocking wild populations. And if this could happen within a cleanly described genus like Poecilotheria, just imagine the implications on some of the genera that are currently in desperate need of revisions. Until recently, Avicularia and Aphonopelma were a muddled mess, and Pamphobeteus and Phormictopus are full of undefined and overlapping species. Many of these spiders are being bred without a full understanding of exactly where they came from or even what species they are.

As an example, a few years back folks started selling a spider labeled as Phormictopus sp. green. Eager to produce offspring of this new species, some folks sought to pair up their females by finding sp. green males for their projects. However, a problem soon arose. Many hobbyists were unaware that there were currently THREE variations of the sp. greens, including “full green”, “green femur”, and “gold carapax”. Because these groups hadn’t been studied yet or described, there was no way to tell if they were color variations of different species (cancerides in some cases) or totally new species. It’s impossible to determine how many people might have accidentally crossbred the green species, and one has to assume that the bloodlines for these three spiders have likely been mixed in some cases. As this spider is still relatively new to the hobby, and there aren’t many currently available, a potential mixing of species could have a disastrous effect on the purity of future bloodlines.

But any hybrids would be sterile, so it won’t become an issue. In many cases of species hybridization, the offspring are sterile, meaning the genetic pollution stops there. Although hybrids can occur, the offspring of such a pairing will be unable to produce young and spread their genes. It’s like nature’s way of keeping species pure in the instances when they are able to successfully crossbreed. Many operate under the assumption that all hybrid offspring are sterile, meaning the mixed genes couldn’t move past one generation. Even if a keeper was to successfully hybridize two species of tarantulas, the offspring wouldn’t be able to reproduce anyway, so there would be no future impact on the hobby.

Hybrid tarantulas have proven to be just as fertile as their pure counterparts. Unfortunately, this rule does not always hold true with tarantulas. Offspring of crossbred species have often proven to be just as fertile as their purebred counterparts. This means that any mixed species that is sold and enters the hobby could potentially be bred and allowed to pass off its mixed genes. This creates a terrible cascading effect as future generations reproduce, spreading their mixed bloodlines throughout the hobby.

Brachypelma baumgarteni/boehmei hybrids: In nature, these two species are separated by the Balsas River, so there should be little opportunity for natural hybridization. However, the hobby is now rife with hybrids due to accidental cross breeding. Many folks who thought they were buying purebred B. boehmei slings later discovered that their spider was mixed with another very similar species, the B. baumgarteni. This situation was further exacerbated by a supposed purposeful mating of these two species several years back. Offspring from this pairing were knowingly sold off and distributed into the hobby (my specimen is likely one of these). Although the issue with the “boegarteni” hybrids is fairly well recognized by now, there are still many in the hobby who have no idea that their boehmei specimens aren’t purebred.

Just think of all the cool colors and patterns we could get. One of the most popular arguments for purposeful hybridization is that it would be a “cool” experiment to see what the offspring look like. Folks in this camp are only concerned with the aesthetic aspect of such an endeavor, and worry little about any of the possible consequences of such a breeding. The thought process can be boiled down to Species A looks nice and Species B looks nice, so their offspring will look totally awesome, right?

Nature already offers us plenty of color and variety. With over 100 genera and 900 species of identified tarantulas, there are more than enough unique colors and patterns without humans endeavoring to create more. Time would be much better spent trying to reproduce some of the beautiful ones nature has provided us.

But if a keeper doesn’t sell the offspring, what’s the big deal? Those who take this stance often adhere to the argument that as long as the slings aren’t sold, there should be no issue. After all, who is it hurting? Folks in this camp often see the tarantulas as possessions rather than animals and pets. It’s therefore no one’s business if they decide to mix some of them up to see what results they get. After all, they’re not abusing their animals, but merely letting them act out their natural instincts.

The amount of work needed and the risk involved far outweigh any reward. Let’s consider the logic in this for a moment. First off, we are already quite familiar with the species that can be successfully crossbred, and there’s really no further experimentation needed in this area. Most would agree it’s a bit pointless to run an experiment for which the outcome is already well known and accepted. If the keeper wants to experiment with breeding, then it would make sense to do so with pure species (there are still plenty out there that folks have trouble with).

For anyone thinking of creating cross-species, it’s important to take a moment to consider the consequences of a successful hybrid mating attempt.

First, many spiders produce sacs containing 100s of spiderlings. This is a lot spiders to be raised, and a lot of money and time spent, for absolutely no payoff. Having raised a sac of slings, I can say that it is very time intensive and costly, with the reward coming only after the slings are sold and traded. I think it’s very difficult for any established hobbyists to believe that someone would want a collection consisting of 100s of worthless hybrid spiders.

Some folks will say that they could just freeze and euthanize most of the slings and keep a handful to raise for their collection. Personally, I think that’s a pretty deplorable stance. Why bother breeding an animal just to kill most of the offspring? In the US particularly, we are behind the 8 ball in terms of sustainable captive breeding projects. It seems rather profligate (and more than a bit cruel) for a keeper to spend his time breeding a mixed species just to destroy it.

Others say that they’ll just raise the hybrids and keep them in their own collections. That’s a wonderful notion, but with so many species available, why would someone want to spend years raising a bunch of worthless mutt spiders to maturity? That certainly doesn’t seem to be a very appealing experiment.

The fact is the temptation to sell off some of these slings would always be there. And as hybrids are considered worthless by most, these slings will likely be mislabeled as a pure species to help them move. Also, some species can take years to mature, and lot can happen during that time. If the keeper has to get rid of his or her collection, what happens to the slings then?

Hobby form of Brachypelma albopilosum Perhaps the best example of hybrids in the hobby is the Brachypelma albopilosum “hobby form.” Due to purposeful crossbreeding with other species (usually B. vagans), the hobby is currently full of B. albo hybrids. These mixed species spiders had been passed along for years as true B. albopilosums. At this point, many consider the only “true” albopilosums to be wild caught specimens from Nicaragua.

But doesn’t it happen in nature? Another argument is that it isn’t a huge issue to mix species, as it likely happens at times in nature. As similar species often have territorial boundaries that intersect, it stands to reason that world may already be filled with many naturally occurring hybrids. There’s no way of telling if some wild caught specimens that entered the hobby could be cross species.

Crossbreeding occurring in nature and crossbreeding occurring in someone’s living room are not the same. There’s a big difference between two similar species crossing natural boundaries and mating in nature and some guy dropping a male and female of two different species in a plastic tub full of dirt so they can mate. It can hardly be argued that there is anything “natural” about a human being playing God by purposefully mixing DNA. There is absolutely nothing natural about that.

My $0.02

Personally, I see absolutely no reason for anyone to purposefully crossbreed two different species of tarantulas. We already know it can be done, and there is really nothing to be gained from a successful attempt. In terms of pros, you may end up with a unique-looking spider that you can show off to family and friends (most serious hobbyist will not be as enamored by it). That’s about it. In terms of cons, you’ll be left either caring for or euthanizing hundreds of spiders or worse, selling them into the hobby at the risk of ruining bloodlines.

In the movie Jurassic Park, Ian Malcom says about the genetically engineered dinosaurs, “Your scientists were so preoccupied with whether they could, they didn’t stop to think if they should.” In many ways, this quote perfectly sums up the situation with purposeful hybridizations. Keepers become so fascinated by the idea of whether it will work and what the offspring might look like, that they don’t bother to ponder the consequences for such an experiment. And traditionally, yelling at them on a message board and telling them what they can’t do with their animals does little to deter the activity. Education on the pitfalls of hybridization is the key; not admonishment.

I’ve heard folks suggest that hybrids could be sold as long as they are clearly labeled at hybrids. Unfortunately, the majority of hobbyists want nothing to do with crossbreeds, meaning demand for them would be quite low. This would increase the temptation to mislabel them as purebreds in order to sell them. Also, just because the spiders start off being clearly labeled as hybrids doesn’t mean that they will remain labeled as they are disseminated into the hobby. These crosses could easily be mislabeled and bred later on, allowing for the impure genes to be spread.

In many ways, tarantula hobbyists may reluctantly and unintentionally end up being the stewards for these amazing animals. As global climate change and habitat destruction inevitably decimates the already shrinking populations of many species, they may only continue to exist in the collections of arachnoculturists. It is therefore imperative that we keep the gene pools as clean as possibly by avoiding ill-advised (and useless) hybrid breeding projects, and while doing our best to ensure that suspect animals are not bred.

On a personal note, I already have three suspected hybrids in my collection, and I didn’t purposely purchase a single one of them. In the case of all three, it took me several years to suspect that anything was different about them. Furthermore, I when I picked up my third hybrid, I only had about 30 tarantulas in my collection. That means at that point, 10% of my collection consisted of hybrid species. That’s an alarming number, and a bit of an eye-opener when comes to appreciating just how bad the problem could be.

As hobbyists, we need to be responsible and protect the purity of the species we keep, and use our energies constructively by only pursuing legitimate breeding projects. The United States especially lags behind Europe in terms of creating sustainable captive breeding efforts for many species. A good percentage of the slings sold in the US are imported from captive breeders overseas and do not represent US stock. Any breeding efforts should be concentrated on pairing pure species to establish them firmly in the hobby and not wasted on crossbreeding.