You mention hybrids on online and there’s a 50/50 chance you’ll get lynched. Hybrids are taboo amongst many herpetological circles and it’s quite obvious why. Sometimes.
There are other occasions where you find yourself asking why?
This was one of those occasions.
Penny and I went on a road trip with our dear friend, Uncle Ken.
Now, what Uncle Ken doesn’t know about anything with scales, fur or feathers you could write, in fairly large handwriting, on the back of a postage stamp. Ken is incredibly knowledgeable and knows a great many old characters in the animal world.
But, and probably the best thing about him, he’s always willing to learn more. This is why we get on so well. None of us has ever said “right, I know everything” and taken it as fact. We always dig for answers, ask the awkward questions and then, question every answer we find.
So, when Ken says to us, “road trip”, we already know its going to be interesting.
Getting the Boot
Off we went on an adventure to collect a, dare a I say it, hybrid snake from a renowned local breeder. Ken got the stunningly beautiful milksnakeXcorn he was after and we, not going there to buy anything I’d like to add, came home with Boot.
Boot or Bootlace to give him his full title, is a pueblocorn, a Puebloan milksnake corn snake hybrid. We took Boot on as he is small, skinny and needs someone to fight for him a little. Enter me and Penny.
These are two species that would not, or very, very infrequently mix in the wild. They do not historically share habitat. So why would they be hybridised?
People. That’s why.
The case for hybrids
Perhaps the most obvious argument is simply diversity. Reptile breeding has long involved selecting animals for unusual colours, patterns and other characteristics. Hybridisation takes that experimentation one step further by combining genetic material from different species.
The results can be visually extraordinary. A Pueblacorn may combine elements of the contrasting bands of a Pueblan milk snake with the colours and dorsal patterning associated with corn snakes. Because inheritance between species can be less predictable than established morph pairings, part of the attraction is precisely that the breeder does not know exactly what will emerge.
There is also nothing inherently pathological about being a hybrid. Hybridisation occurs naturally throughout the animal kingdom, including among reptiles. The biological boundaries we call species are not always absolute reproductive barriers.
Consequently, the welfare question cannot simply be answered with “hybrid = unhealthy.” If two species can produce viable offspring, and those offspring develop normally, feed normally, behave normally and experience good welfare, the fact that their parents belonged to different species does not itself demonstrate harm.
There is also a legitimate element of scientific curiosity. Breeding hybrids can reveal interesting things about inheritance, phenotype, fertility and the evolutionary relationships between animals. For private keepers, much of that curiosity is informal rather than scientific, but curiosity itself is hardly an unethical motivation.
And there is clearly a market for them. Some keepers actively seek hybrids precisely because they are unusual.
The case against hybrids
The strongest criticism, however, has relatively little to do with whether an individual hybrid can live a perfectly healthy life.
It concerns what happens afterwards.
A Pueblacorn sold accurately as a Pueblacorn presents relatively little ambiguity. Its new keeper knows what the animal is and can pass that information onwards.
But animals change hands.
A snake may pass through several owners during a lifespan measured in decades. Documentation disappears. Breeders stop breeding. Keepers leave the hobby. Animals are surrendered to rescues. Eventually somebody may possess an animal whose ancestry amounts to little more than “I was told it was a corn snake.”
If a hybrid strongly resembles one parental species, it may subsequently enter breeding populations as an apparently pure animal.
That is where hybridisation can affect considerably more than the original clutch.
Once undocumented hybrid ancestry enters a captive lineage, removing it becomes extremely difficult. An animal may appear phenotypically normal while carrying ancestry from another species several generations previously.
For breeders attempting to maintain known locality animals, established lines or genetically representative captive populations, provenance matters.
There is another legitimate criticism: why produce the animal at all?
Producing something simply because it looks unusual is not automatically unethical—if it were, a substantial proportion of reptile morph breeding would require the same criticism. But novelty cannot absolve breeders of responsibility.
The more experimental the pairing, the greater the uncertainty surrounding the offspring. Adult size, morphology, behaviour, reproductive capability and even husbandry requirements may not fall neatly between those of the two parental species.
The breeder therefore assumes responsibility for uncertainty that they deliberately created.
Just because we can
And perhaps this is where the question of hybrids becomes less about hybrids at all.
We know that we can produce them. Boot is currently sitting in front of us providing fairly conclusive evidence of that. The more important question is whether the ability to produce an animal is sufficient justification for doing so.
Obviously, it isn't.
But that applies just as readily to pure species and established morphs as it does to hybrids.
Every time we deliberately put two animals together, we are making a decision on behalf of offspring that do not yet exist. We decide their genetics. We decide the circumstances into which they are born. We decide, at least initially, what happens to them afterwards. Whether we're producing a clutch of normal corn snakes, the latest Royal Python morph or something with parents belonging to two different species, the fundamental responsibility remains remarkably similar.
The difference with hybrids is uncertainty.
If I breed two corn snakes, I have a pretty good idea what I'm going to get. I know roughly how large the offspring will become, what they are likely to eat, how they are likely to behave, what environmental conditions they require and approximately how long they may live.
Cross two species and some of those assumptions become less secure.
That doesn't automatically make the pairing unethical.
It does, however, make ignorance considerably harder to excuse.
If we deliberately create uncertainty, then surely we also accept responsibility for investigating it.
And that responsibility cannot end when the hatchling leaves the breeder's collection.
Boot has a label
We know what Boot is.
That sounds ridiculously simple, but it may actually be one of the most important things anyone can know about a hybrid animal.
Boot is not an unusual-looking corn snake. He isn't a strange Pueblan milk snake. He isn't a new morph. He is a hybrid between the two, and anyone who ever takes responsibility for him should know that.
Because Boot may live for a very long time.
Penny and I might not always own him. Records get lost. People forget conversations. Animals are sold, rehomed, surrendered and inherited. Twenty years from now somebody could conceivably acquire Boot with nothing more informative than “He's some sort of corn snake.”
And if Boot is fertile, that matters.
Put an undocumented hybrid back into a corn snake breeding population and the problem doesn't necessarily announce itself with spectacularly hybrid-looking babies. Several generations later, animals carrying hybrid ancestry may look sufficiently like ordinary corn snakes that nobody would know without a reliable history.
This is where I think some of the hostility towards hybrids becomes entirely understandable.
The problem isn't Boot.
Boot couldn't care less about the philosophical argument surrounding his parentage. His priorities are considerably simpler: security, appropriate temperatures, somewhere to hide and, judging by most colubrids I've met, whether something edible might appear shortly.
The responsibility belongs to us.
We know what he is.
Our job is to make sure the next person does too.
Would we do it?
While we were at the breeder’s facility, Penny and I noticed a tub labelled “Turbocorn”. This caught my eye and provoked images of a corn snake on rocket fuel or maybe sporting a small engine. Penny, as usual, was more sensible and asked what it was. The answer had us both a little stunned.
A Turbocorn is a Pituophis × Pantherophis hybrid. So, a gopher, pine or bullsnake crossed with a corn snake.
Does anyone remember Bruce?
Does anyone remember Penny’s passion for corn snakes?
I remembered both at the same time and then started thinking – is this something I could do?
The biological opportunity is certainly sitting there. We have an adult male bullsnake. We have female corn snakes. We have experience breeding colubrids, incubating eggs and raising hatchlings. We have the equipment. We have the space.
In other words, we probably could.
Which rather inconveniently brings us straight back to the title of this article.
Just because we can.
If I'm going to question the responsibility of people producing hybrids, I don't get to exempt myself from exactly the same scrutiny simply because I really, really want to see what Bruce crossed with one of Penny's corn snakes might produce.
So before a single animal gets introduced, I need better answers than “because it would be cool.”
Would the offspring be healthy? What do we know about existing Pituophis × Pantherophis hybrids? Are they fertile? Are there developmental abnormalities associated with the cross? What happens behaviourally when you combine two animals with rather different natural histories? What size should we expect? Which parent's husbandry requirements should inform how the offspring are kept? And perhaps most importantly, what happens to every animal we produce?
Because these wouldn't simply be unusual corn snakes.
They would be animals whose existence Penny and I had deliberately engineered.
That means we would need to know exactly what we were producing, document the parentage of every hatchling, make their hybrid status absolutely explicit and ensure that anyone taking one understood what they were buying. If uncertainty exists around their eventual size, behaviour or reproductive potential, that uncertainty needs to travel with the animal too.
And if we cannot answer those questions satisfactorily?
Then Bruce keeps his trousers on.
That might be disappointing. It might mean walking away from something genuinely fascinating. But responsibility isn't demonstrated by being willing to breed something unusual.
Sometimes it is demonstrated by being willing not to.
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