As regular readers will be aware, I’ve got a particular love for colubrid snakes (snakes of the family Colubridae, which includes king snakes, rat snakes, milk snakes, and many others). To that end, I’ve expanded the menagerie recently with two new additions: baby corn snakes, Pantherophis guttatus guttatus. Hypatia and Daedalus.
Since corn snakes require virtually identical care to king snakes, which I’ve already covered in a previous post about Penelope, my California king, I’ll avoid repeating myself and instead focus on some of the other interesting aspects of my new little friends. There’s also lots of reputable websites out there with excellent basic care information, and I’ll link to a few of them at the end of this post.
Now, someone not particularly familiar with snakes might look at those photos I posted up above and say, “wait, those aren’t the same type of snake!” But looks can be deceiving, and yes, they are both corn snakes. Corn snakes have, however, been a popular pet species for several decades, and in that time there have been many captive breeding projects aimed at producing interesting, and incredibly varied, colour morphs. Hypatia is what is known commonly as a “butter” corn snake, while Daedalus is a “lavender”. Neither of these are colours that you’d be likely to see in the wild. But in captivity, there’s been a lot of success with producing a great variety of morphs, and captive-bred corn snakes are now available in almost every colour you can think of (not in blue, yet, but I’m sure there’s someone working on it as we speak).
How these different colours are produced is actually quite interesting, if a little bit complicated. To begin with, there are several different “wild types” of corn snakes. These are corn snakes that, because of being geographically isolated from each other, have evolved to have slightly different colours and patterns. The Keys corn snake is a pinkish hue, and tends to have a slightly smaller adult size. Miami corn snakes have grey or very light tan bodies, with dark orange “saddles” (the splotches on the back) outlined in black. Okeetee corns (found on the grounds of the Okeetee hunting club in South Carolina) have bright orange bodies with dark orange or red “saddles”, and the saddles have thick, black outlines around them. And finally, there’s the Carolina (or “normal”) corns, which have bright orange bodies, dark orange or red “saddles”, and thin, often incomplete, black outlines around the saddles. Any of these “wild types” will act as dominant, while other colours may be present as recessive traits, hidden invisibly in a snake’s genetics.
In the wild, with so many snakes interbreeding with one another, it would be unlikely for two snakes with the same recessive trait to meet and produce eggs. But get snakes into captivity, and the available gene pool shrinks considerably. Inbreeding tends to bring out recessive traits, and in captivity, that’s what happened.
So far, we know of more than a dozen different genes that can affect a corn snake’s colour and pattern. Several produce similar effects (there are 4 different strains of hypomelanistic, or albino, corn snakes to be found, and it’s difficult to tell the difference between them just by looking; you have to know your snake’s lineage to be sure if it’s a hypo, a sunkissed, a lava, or an ultra). Others are quite unique (the Palmetto morph, for example, is particularly striking, and certainly hard to miss). Other genes don’t affect the snake’s colour, but change the shape of its pattern — Motley snakes have dots instead of saddles on their backs, while Stripe morphs are, well, striped.
It doesn’t just stop there, though. Because each of these colours or patterns is produced by a different gene, you can get snakes that exhibit multiple different recessive traits at once. Butter corn snakes, like my Hypatia, are such a combination: a butter corn must have both the “amelanistic” and “caramel” traits. And it’s not just as simple as taking a caramel-coloured father and an amelanistic mother and breeding them together: it takes several generations to produce a line of snakes with such a combination of traits, because you have to eliminate any “normal” genes, which would dominate over the recessive traits and thus the snake would appear just like a wild-caught specimen. Even harder is combining 3 or 4 traits — but with patience, almost any number of combinations can be achieved. It can be a bit of a gamble for breeders, though — while combining 4 different traits could produce something never before seen in the pet trade, it won’t do you much good if the resulting snake looks boring, or too similar to something that’s more easily produced.
A Basic Corn Snake Genetics Lesson
If the above paragraph left you feeling lost, I’ll try to make it a bit more simple here.
Say a corn snake has 4 different genes that can code for 4 different colours (they have a lot more, but I’m reducing it here to make the example a lot more simple). We’ll call those genes N (for normal, like a wild-caught snake would be), a (for amelanistic), c (for caramel), and l (for lavender).
Now, each snake would have two copies of each gene — one from their mother, and one from their father. Because N is dominant, while the other genes are recessive, a snake needs 2 copies of the same recessive gene in order to express (show) the colour for which that gene codes. Otherwise the dominant N would be the thing that ends up showing.
In this example, Daedalus (my lavendar corn snake) would have two l genes coding for lavender, but only N genes in the places that might code for caramel or amelanistic. So a chart of his genetics would look like:
lavender l l
Hypatia, on the other hand, would have double-recessive genes for both amelanistic and caramel — but since she doesn’t express a lavender trait, she’d have N genes there:
amelanistic a a
caramel c c
Now we’re going to complicate matters. If Hypatia and Daedalus were to have babies together, their babies would all look like normal, wild-caught corn snakes, because each one would receive one recessive trait from one parent, and one dominant trait from the other. The dominant Ns would be what showed up — but all of the babies would be what is called “heterozygous” for all 3 traits, since they’d have the recessive traits still hidden, unexpressed, in their genetic codes.
__________from Dad from Mom
amelanistic N a
caramel N c
lavender l N
But if we were to breed those babies together with each other, that’s where it gets really interesting, because now there are many options for what each parent could contribute to the genetic mix. This website is great for calculating the odds of what you’ll get from parents with known genetics, and from that we can see that there’s a 1 in 64 chance that you’d get a baby with all 3 traits expressed: caramel, lavender, and amelanistic together. The vast majority of the babies (27/64) would be just like their parents — normal in appearance, but with hidden genetics lying unexpressed beneath the surface. Some would have one, or even two of the traits expressed, giving you some amelanistic babies (9/64), some caramel (9/64), some lavender (9/64), some butter (3/64), some caramel/lavender combos (3/64), and some opal — a combination of amelanistic and lavender — (3/64).
This is, essentially, the same way that human genetics work. Just like blonde hair and blue eyes are recessive and may be “hidden” by dark hair and eyes, so may various corn snake colour traits remain hidden for many generations, until a limited gene pool (or sometimes just random chance) brings them out.
Less Complicated Things
All right, so that was still rather complicated. Genetics are kind of weird, although once you get the hang of it, they’re very much predictable. But let’s move on to some of the less complicated reasons why corn snakes are so interesting.
Corn snakes are fairly common in the wild, being found all across the southern U.S. and down into northern Mexico. They live in a huge variety of habitats, from the arid climate of Texas to the damp woodlands of Florida, from sea level to as high as 6000 feet in elevation. In cooler areas they will hibernate through the winter, but in more temperate climes they’ll simply go into a period of reduced activity between December and March, spending more of their time hiding in rock crevices and less out hunting and basking in the sun. This winter cooling, or “brumation”, is actually a necessary part of their breeding process — without a brumation period, snakes won’t readily breed in captivity.
Like most snakes and other reptiles, corn snakes do not care for their young the way that mammals and birds do. After laying her eggs in a warm, moist location, the female corn snake goes away to resume her normal life. The eggs are left to incubate by themselves (not a problem, since they incubate safely at a wide range of temperatures, anywhere between 72 and 90 degrees, which in their habitat is a relatively normal summer temperature). Depending on temperature, the eggs will take 50-60 days to fully develop. The baby snakes that hatch out are completely independent, ready to go out hunting almost immediately for their very first meal.
In the wild, corn snakes are sometimes mistaken for venomous snakes such as copperheads and killed by ignorant humans. But these shy little snakes can be a great help in keeping down the numbers of pest species such as rats and mice, and so they should be encouraged to live in your yard if you happen to be in an area where they are native (plus it’s just nice to have cute little snakes in your yard!) Corn snakes, while not endangered, are at risk from habitat destruction, and so by creating a place that is safe for them, you are protecting your local biodiversity.
While corn snakes usually like to stay on the ground, they are excellent climbers. In the wild they may climb up trees to get at bird eggs or other delicacies, while in captivity they will explore every inch of their tank and may even amaze and baffle you by climbing up the bare glass, like Hypatia is in this picture:
They are also incredibly good at finding absolutely any hole or gap in their enclosure through which they might escape, and so it’s very important, if you want to have a corn snake as a pet, to buy a tank that is specifically designed for keeping snakes, and to check it carefully for any little gaps and spaces (note the bit of duct tape on Hypatia’s tank in the photo above — that’s covering up a tiny space where the lid clips on to the tank). Corn snake escapes are unfortunately rather common, and they can be hard to find again once they do get out. Protect your baby (and show courtesy as a pet owner) by making sure they can’t pull a Houdini on you.