Is there a herpetologist in the house?

August 18, 2010 7:00 AM

My son's pet California King snake is acting very odd. Does anybody have an experience with this behavior in snakes? The snake is about 6-7 years old, bred in captivity. We've had him since he was a little less than a year old. He is 4 feet long and eats 1 adult mouse (frozen) a week at this time of year. Google turns up a handful of snake forum posts describing this same behavior, but no real answers.

Sunday night we found him chewing on his own tail - a few inches up from the end. We had just fed him 3 days prior, but he had shed his skin the week before and he normally won't eat in the last week or two when he is shedding. So we thought he was just over excited in feeding mode after the break from eating and mistook his tail for another snake. We gave him another mouse and all seemed back to normal.

Last night he was latched on to his tail again, this time a little farther up. He is not swallowing his tail from the end like he would if he was ingesting something. He is biting himself from the side. Taking him out of the acquarium, holding him in front of a fan, and dunking him in his water bowl did not get him to release. There was blood on his tail too from where he was biting himself. We tried feeding again, and even that didn't get him to release. Thinking maybe his fangs got stuck, I used a plastic spoon and gently worked it under his upper jaw, which did finally get him to let go his tail. After zooming around the aquarium for a few minutes, agitated and striking at the sides, he noticed the mouse and ate. After that he seemed more or less back to normal and this morning he is quietly relaxing in his rock digesting the mouse.

I have found the local exotic vet but before racking up a vet bill I thought I'd ask here. We've looked the snake over closely and don't see any signs of mites. Physically, he seems fine - no obvious sign that he may be in distress - other than the biting himself thing. His home is a 20 gallon aquarium, with is 24 inches long. The snake is 48 inches long. By the book, that might be little small of an enclosure, but the snake has been 4 feet long for 3-4 years and has never shown any sign of not thriving in his current environment. He has hollow rock to hide in, plenty of clean substrate to burrow in, a water bowl that he can soak in, and a fake branch to climb on. In short - everything a captive king snake should need. Plus my son does take him out regularly. We don't see any sign of mites, and constipation is not the issue either. The next thing to try I think is a larger enclosure, but I'm not really convinced of that being the problem.

Any ideas?

(Posted on COD's behalf.)

posted by brownpau to pets & animals (8 answers total)

I used my question earlier this week on a work related software issue, and then this came up so I hit up brownpau to post on my behalf.
posted by COD at 7:05 AM on August 18, 2010

Have you tried feeding him two mice instead of one? I have a 4 foot adult corn snake and he is still visibly hungry and in hunting mode if i only feel him one mouse. Once I give him a second one he relaxes and digests. He generally eats about every 12 days.

Also, how are are you providing heat for him? I would definitely check your cage temperatures at the substrate level with a digital probe thermometer. For a california king, you generally want a temperature gradient from 75-ish on the cool side to about 85-90 on the basking side.
The biggest downside to a 20 gallon aquarium is that it's difficult to keep a correct temperature gradient in the limited space you have. If your cage temps are way off, that may have something to do with the odd behavior.
posted by d13t_p3ps1 at 7:38 AM on August 18, 2010

Oh, and I just thought of this...for most snakes you want to have a hiding spot on each side of the tank. Sometimes they won't move if they are too hot/cold unless they have somewhere else secure to move to.
posted by d13t_p3ps1 at 7:39 AM on August 18, 2010

What you describe is not new to me, and is something I've associated with kingsnakes for a while. Not that other snakes don't try to bite or swallow themselves -- I had one garter snake do just that in the past month -- but I've had more than one kingsnake do this to itself on more than one occasion.

My pet theory -- little more than a joke, actually -- is that kingsnakes are really dumb: stupider than they average snake (whose brain functions, I've also joked, could be expressed in about 30 lines of Perl). Kingsnakes are known as snake eaters (which is why you can't have more than one in a cage as a rule), and are immune to rattlesnake venom, but will pretty much eat anything. They don't, in other words, discriminate in terms of what they eat; the part of the brain that asks whether something should be eaten has been replaced with a simple NOM! -- I suspect that if it moves and is small enough, they will try to eat it.

I've also observed that captive kingsnakes tend to go a little crazier than other snakes at feeding time -- they tend to lose what little mind they have when attacking their food. Corn and pine snakes, for example, tend to be pretty placid feeders, so much so that I've been able to feed them on my lap; I wouldn't dare do this with a kingsnake. They. Just. Freak. Out.

Now, remember how I said one of my garter snakes did this earlier this month? I've also noticed some garter snakes freaking the crap out during feeding time -- especially that one, his brother, and his father, all of whom would bite willy-nilly at everything that moved, except, of course, the food. (Among garter snakes it seems to be a male thing: males are pretty hyper to start with; females are much calmer and matter-of-fact about eating, though they have much bigger appetites.)

Another factor: I've never seen a snake hungrier than just after it's eaten. In the wild, snakes tend not to eat at regular intervals: they raid an entire mouse or bird nest, or gobble down many frogs just after they're transformed. Food is not available regularly, so they tend to gorge when it's available. Feeding mode is like a switch that is left on for a while.

I've also seen snakes bite their cagemates immediately after feeding, but only then.

My best guess is that certain snakes lose their shit when feeding, and in the confusion bite themselves, thinking it's more food. Eventually they settle down -- so it's not like you have to worry about the snake turning itself into Ourobourous 24/7. Only in the immediate aftermath of eating.

Regarding cage size: a 20-gallon cage is a little small for a four-foot snake. My California kingsnake is about the same size as your son's, and is in a 25-gallon cage; I wouldn't put one in anything larger than a 30-gallon, though. While a larger cage would help in general, I don't think it's pertinent to this particular problem.

I also have some experience at getting a kingsnake to release its jaws -- not from biting itself, but from biting other kingsnakes. You see, I tried breeding kingsnakes a couple of times. Unfortunately, the first time I tried it with two females -- oops. The second time, they just weren't in the mood. In both cases, the larger snake grabbed and constricted the smaller. They were separated under cold, running water in the bathtub. Might want to try that next time.

Bottom line: this isn't something a vet can do anything about.
posted by mcwetboy at 7:45 AM on August 18, 2010 [6 favorites]

My son has been leaving the infrared lamp off at night - since it's 78-80 in his room anyway. And both incidents were at night too. He is more active at night, so it may simply be that. He leaves the daytime lamp on so that there is a nice 85-90 degree spot for Blackbeard, but turning the infrared back on at night is worth trying.
posted by COD at 8:30 AM on August 18, 2010

The rule of thumb for most North American colubrids -- at least the ones people keep as pets -- is 75-85°F, and I generally go cooler than that at night. If anything it may be too warm in there.
posted by mcwetboy at 9:23 AM on August 18, 2010

Apparently this is not unknown for kingsnakes...
posted by The otter lady at 9:26 AM on August 18, 2010

Update: Changing his feeding schedule from 1 mouse a week to 2 every 10 days seems to have settled the snake down. He hasn't tried to eat his tail again since. Thanks for the help.
posted by COD at 8:29 AM on September 11, 2010