I have done several skulls now and I recently had a boar skull in my bug box for awhile. It was not an old skull. It has not been boiled or bleached. I went to take it out today and the side it was laying on is somewhat deteriorated. Parts of the bone are missing and parts of it are brittle and crumbly. What could have caused an otherwise good skull to go bad? Any ideas?
Return to Gamehead Taxidermy Category Menu
Is there a high ammonia smell? Maybe you"re allowing the heat and humidity to rot the skull as well as the bug cleaning?
In addition, how long is "a while"? Bugs should clean a boar that was properly prepped in less than a week.
There was no ammonia smell. I checked the skull every few days to spritz with water. I had removed most of the meat, eyes, and brain, let it dry for a week or so, and put it in the box. It has been in there about 5-6 weeks. After four weeks I added a new colony of bugs, and put in a nesting box to speed them up. I took it out today figuring the meat was too dry and I was just going to rehydrate it when I noticed the condition of one side of the skull.
Sounds like the cartilage that holds sutures together let go. There is a higher risk of this happening through maceration if you don't know what you are doing - but it can happen with dermestid colonies as well. Basically - when the meat is gone or not easy to get too - dermestids will begin to eat cartilage. Since a skull should be cleaned in about 3 days it sounds like you left it in there for far too long thus giving the lil creepers a chance to munch on that cartilage.
So is there anything I can do now? It looks like the skull is destroyed and I will probably have to find a similarly sized skull and just put these tusks in that skull...unless there is a way to fix it? Also, I'm not sure it was the cartilage. The entire cheek (zygomatic) bone is missing and the bones near it can be crumbled in my hand with pressure.
Without seeing your skull in person, or knowing how long it was around before being cleaned, we can only guess what might have happened.
You stated initially that it was "not an old skull". Does that mean that the specimen was a juvenile? or that it was a fresh specimen and not initially prepared long ago? If the bone absorbed large quantities of fat from tissue or brain matter (the brain is something like 40% fat matter), and if your colony is extremely hot and runs out of more palatable food, it can eat the actual bone surface - even the entire skull. This should not happen on a mature specimen, recently prepared UNLESS there was some pre-existing disease that prevented correct ossification in the skull. If it was a juvenile specimen, it is much poorer bone material and it could be damaged by consumption.
The suggestion that ammonia might cause this is not a valid one though. You can soak skulls and bone material in grocery store ammonia for very long periods with very little decomposition. Older dermestid colonies build up an ammonia smell in the base material over time and can lead to persistence of the smell, but if it gets too high the bugs will die. It is best to change aquariums whenever the colony gets the smell.
The specimens I most often notice with a "Bone" disease is captive turtles that don't get an appropriate diet and/or light source. In some zoo specimens I have prepared the bone is extremely crumbly and often leads to death of the specimen.
As far as replacement of the skull - if you had a rider in your contract, then all specimens run the risk of damage when in your control. Thus you shouldn't need to purchase a new skull. The damage was not as a result of anything you had under your control - at least as far as I can ascertain from what you are describing happened.
What I meant by "not old" was freash. The boar skull was about 12" long with 2 1/2" teeth so I think it was pretty mature. It was frozen right away and gotten to me about 3 months after the kill. I thawed it out and it was not smelly. It was somewhat cleaned, but not too well. Now I am fleashing them out a great deal more. This skull had about an inch of meat on it at the most in places.
Mature skulls usually do not just get eaten by bugs. The only time I ever had a mature skull eaten (and I have cleaned over 13,000 skulls/skeletons) was a two bear skulls which had been stored in a freezer for several years. The fat had REALLY soaked into the bones of the skull and I had a very hot colony. Within a week damage was done - even though other portions of the skull still had meat that should have drawn them to that side. Juvenile skulls can often have damage but even certain adult birds, especially owls and Caprimulgids whick have "airy" bones. Perhaps only a dozen skulls ever had real damage, which isn't bad considering the number involved.
As far as how much to cut off the skull. I never leave any more than 1/4 inch of tissue on the bone in any area. It speeds up the eating much better and familiarity with the skull will make the skinning very fast.
I have since then switched to scalpels and am now fleshing down to about what you describe. It seems to be helping.
I totally overlooked this point until I read The Taxidrmologist mention fat. If your skull was very fatty or liek mentionned.. still ahd the brain in it.. the fat may have turned rancid. Once rancid it can turn acidic and thus eat your bone.
My bad for not cluing into that right away.