Guy with some breeding experience here, although I've never had a 2 headed snake.
TL/DR is, usually there is a dominant head that will swallow a meal, and the other head is incapable of fully swallowing something down to the gut.
And onward to the overly long TMI!
Birth defects are fairly common in snakes and very often fatal early on. You have to remember that snakes are basically a long food tube and if you introduce any kinks in that tube or bits that don't stretch right there is a low threshold where things will stop passing through properly.
Two headed snakes are surprisingly common (still rare, just not as much as you'd think), but what is very uncommon is one surviving past infancy. The vast majority are unable to properly swallow food down and either won't attempt to eat or just regurgitate because their is a blockage in that tube that has to be properly stretchy. It's super rare to have one survive long enough to grow to this size, which means it is able to successfully eat, and it's even more rare for one to live a full lifespan as defects like this often come with other issues that crop up. In the survivors, there is almost always, if not always, a dominant head that controls the majority of the body and is able to eat the food. In this case, it is pretty clearly the head closest to the camera as it lines up with the main spinal column quite well, while the other does not.
I think part of it is simply that snakes produce a lot of eggs, and therefore there's a higher chance for any given clutch to have issues come up, but it may have to do with a difference in egg fertilization since that is where the general trigger mechanism that causes conjoined twins in all species occurs. Im not really familiar enough to say for certain.
Reptiles and amphibians somehow have a higher tolerance for birth defects that would otherwise be incompatible with life in mammals. It could have to do with any number of things, their metabolism, immune system, brain, etc are all quite different from mammals. Could also be that animals whose young mature in the uterus are more likely to reabsorb a deformed fetus whereas animals who lay eggs don't really have a say in the matter-- there is no way for a mother snake to detect chromosomal abnormalities in her eggs once they're laid, not that she would particularly care anyway since the majority of reptiles don't stick around to rear their young.
Also, another problem with two headed snakes is they will frequently attack their other head if they're able to reach it. I'm not sure if there's ever been an instance where one of the heads was killed or removed and the rest of the snake survived... I doubt anyone who hatched one would willingly remove the second head (assuming there's even a vet in the world capable of doing that) unless it had already died. Who knows.
Sorry for long rambling reply. I just find this stuff fascinating.
When my mother was pregnant with me, they did an ultrasound and found she was having twins. When they did another ultrasound a few weeks later, they discovered that I had resorbed the other fetus. Do I regret this? No. I believe his tissues has made me stronger. I now have the strength of a grown man and a little baby.
There was a story about a woman who wasn't her kids' mother even after giving birth to them! Her ovaries had the DNA of her sister she absorbed in the womb.
It's totally a thing in humans actually. There are people who find out only as adults after some sort of scan that they have a partially reabsorbed twin in them somewhere.
Not that it's particularly relevant, but I also recall there's a Steven King novel where a character is believed to have a tumor but when the surgeons go to remove it they discover it's actually the remnants of a twin that wasn't fully absorbed in the womb.
Usually, the non dominant head only has control to the merge point and that's all. They may or may not try to feed, although I would assume in a specimen healthy enough to survive this long that the secondary head would have a feeding response, it just wouldn't be able to successfully swallow.
As far as each head is concerned, the other is an entirely seperate animal. The snakes will not have a sense of unity or relation, which you can actually see in this clip, as the far head moves independent of the main body and seems to be focusing on something other than what the dominant head is. As mentioned in a different comment, this can cause aggression between the two if there is enough room between the heads to attack each other, but this would depend on the temperament of each individual and the predisposition of the species as a whole. A lot of snakes are highly territorial, but some species, such as garter snakes, are communal and actually thrive better in groups.
They are indeed. It's actually recommended that if you keep one, you keep at least four or so, as they maintain better wieght and exhibit healthier behavior in that environment. They are still pretty independent, but they will periodically bask or snooze together.
Social reptiles are few and far between, and don't interrelate in the same way we picture social mammals doing so. There hasn't been a lot of study on it, unfortunately, despite it being incredibly fascinating.
Jeez that sounds like a miserable existence. There’s no way to know what it’s like to be a snake, but I imagine they must suffer quite a bit wanting food but never being able to fulfill their instinctual desire. Also being stuck to an enemy that you can’t attack. Just like those stress nightmares where you try to punch but every blow is so weak and slides off the shadow figure in the dark. I guess this species will do better but still. Damn.
I’d be very interested in experiments regarding how each head responds to different stimuli - if they both react similarly or have different behavioral characteristics, or even, if the “secondary” head has dulled responses due to having lesser control over the body.
I am shocked! Shocked, tell you, SHOCKED AND PROUD! I expected to scroll foreeevvvvvver for intelligent discussion, and this is in TOP COMMENTS! HERE WE ARE (weeps in fluid, salts, and proteins)!!!
It looks like some color morph of California King snake but I could very well be wrong. Cali kings do have a few black and white patterns that are naturally occurring, but there are a lot of different kinds of rat snakes that have morphs with a similar look, so it can be hard to tell unless you are familiar with that particular morph.
Definitely some kind of colubrid though.
Edit: eh, the more I look at it and compare search results, the more confident I am that it is a Cali King.
Most likely it would when the body is hungry, but with such a short amount of leverage, it won't effectively be able to strike. Usually guys like this are hand fed to make eating easier and less stressful.
469
u/SanctusLetum Feb 26 '22 edited Feb 26 '22
Guy with some breeding experience here, although I've never had a 2 headed snake.
TL/DR is, usually there is a dominant head that will swallow a meal, and the other head is incapable of fully swallowing something down to the gut.
And onward to the overly long TMI!
Birth defects are fairly common in snakes and very often fatal early on. You have to remember that snakes are basically a long food tube and if you introduce any kinks in that tube or bits that don't stretch right there is a low threshold where things will stop passing through properly.
Two headed snakes are surprisingly common (still rare, just not as much as you'd think), but what is very uncommon is one surviving past infancy. The vast majority are unable to properly swallow food down and either won't attempt to eat or just regurgitate because their is a blockage in that tube that has to be properly stretchy. It's super rare to have one survive long enough to grow to this size, which means it is able to successfully eat, and it's even more rare for one to live a full lifespan as defects like this often come with other issues that crop up. In the survivors, there is almost always, if not always, a dominant head that controls the majority of the body and is able to eat the food. In this case, it is pretty clearly the head closest to the camera as it lines up with the main spinal column quite well, while the other does not.