Raven,
Have you ever had the chance to compare various methods of cleaning skulls, and methods of degreasing them, and methods of bleaching them, and the combination of them, to know which way has the least impact on the shrinkage of a skull during the 60 day drying period required by B&C and P&Y. I did check the search button but I wasn't satisfied with the responces. Besides being a taxidermists, I do measure for B&C and P&Y. I can tell you all of the meat and membrane must be removed before a bear or cougar skull can be measured. The beetles probably would solve this part. I do not want to wait 2 months to degrease something if it would be harmful to the skull down the road. If I'm going to degrease it, then I might as well put it in peroxide if it isn't going to make a difference.There is a question in there somewhere. "Thanks."
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From anything I have seen... the various methods used for cleaning, degreasing whitening, etc won't matter for scoring. Skulls can't shrink or expand THAT much to effect score (my opinion). If it swole that much it would buckle and break... if it shrank that much it would simply fall apart. The slight expansion and contraction rates that happen *I* don't think would be enough to effect measurements at all - but can cause problems in terms of suture fit and movement between the various bones that make up the skull. So for skull integrity it can play a role but as far as you are concerned with scoring - I wouldn't worry about it that much. Maybe someone else has different views on it or other experiences?
Not sure what your comment about waiting two months to degrease it was referring too... I'm guessing you are talking about a cleaning method? I can't think of any method right now that would take that long.. manure pile maybe.. all other methods are pretty fast tho. You certainly don't wanna macerate a skull for that long - it will fall apart on ya most likely when the bacteria dissolves the cartilage. At that point you just have to hope the sutures are tight and holds the skull together kinda like lego - LOL!
As for other stuff - I'm waiting until I get more skulls and bones of my own to play around with some other ideas. I have some ideas for making smelly bones nicer to handle using various organic and chemical methods. I'm also loking into ways to degrease that are more harsh BUT I have some theories about recalcification to counter it. I want to research acid baths more as well. That's something I got interested in my college days studying fish and wildlife biology but didn't get to fully explore. I don't know if anything will come of these experiments - but I have some questions and hypothesies that I want to try and find answers to. Not sure if that ties into your pseudo question - but if theres something you can gain from this - cool =)
Raven
Thanks for getting back to me on this. I was refering to the 2 months in that, if I had the beetles clean the skull and waited the required 60 days to officially measure it, before degressing and using peroxide it would be two months. I wasn't sure if the grease would then be harder to remove if not taken care of right away. All skulls should have a different measurement after the 60 day drying period. My concern was that in your experience you may have found something that had negative effect on a skull. A lot has been written about boiling but I also was wondering about acetone instead of a commercial degreaser or a strong peroxide solution, would have an effect. The reason for the question in first place was not to take away from the skull and still have the score hold up down the road if it needed to be remeasured. I'm guessing the answer to my question really is moderation. Beetles, a mild but effective degreaser and a not too strong whitining solution. Again thank you for getting back to me on this. Wayne
There is certainly a bit of shrinkage in both horned animals and in skulls themselves, but I am unaware of any research that has investigated how much actually happens. I have measured deer antlers fresh and a year later and was surprized that on a set about 141 fresh, shrunk to circa 138. In the fresh state, even though the antlers are dead material, they are often just recently dead. In the fall also, the humidity is higher in the out-doors, and the porous material would be full. When the antlers come back into a heated house (at least up north) the humidity is much less inside, and a good amount of shrinkage happens. Various methods to try and counteract this in antlers that I have heard - has been to freeze-dry the antlers during the 60 days, or to put a two-by-four between the antlers that is snug to prevent the skull from closing further and reducing the width. Some even use methods to increase spread.
Not to pick on Raven (especially when I don't have the time to answer all these questions and he pretty much spends lots of time here), but I would disagree with his statement of "Skulls can't shrink or expand THAT much to effect score". There is an overall shrinkage in the entire skull so that all parts shrink together, so there is no cracking apart. (Actually, there is cracking in the teeth on many occassions because the enamel (which does not shrink as much) is attached to the underlying bone material which DOES shrink). A bear skull shrinkage of 1/8th inch lengthwise and 1/8th inch widthwise makes a very significant 1/4 inch in an overall measurement, and in many cases there may be more than a total 1/4 inch shrinkage. The person I would contact for his opinion would be Perry Kline at pgk@ncentral.com who is a registered measurer and a taxidermist. There may be methods that are illegal to do - perhaps even what I am about to suggest.
So, the trick is to get all the material off of the bear or cougar skull without allowing the skull to get shrunk by humidity reductions. I would suggest that you use a dermestid colony with a humidity control which is reasonably high. Prepare the skull and only dry it overnight and place it directly in the colony. You can leave it for a couple weeks or so to clean off all the tissue on the skull completely so that only a frass rincing and degreasing would be needed. Then when completed, I would transfer it to 50% solution with water of ammonia purchased in a grocery store. The ammonium ion will not replace the calcium in the bone material and because of the lower pH by dilution, I don't believe the collagen is affected that much. Breakdown of this can result in further shrinkage. Anyhow, ammonia will degrease the skull slowly, and with a change in solution whenever it gets greasy or yellow colored, with sufficient changes over the remaining 60 days, most of the grease will be removed. Three days before you are to get the skull measured, rince it in water for an hour, then dry slowly in a humid room. If you dry it too fast there is a likelihood the canine teeth will crack just overnight. If you live in a humid environment, often the teeth will never crack. Anyhow, by the third day the skull may be entirely dry to the touch and look completely clean. However, it never got the opportunity to go completely dry. Measure it - once done this way may score it higher than it would if you prepared it by simmering, and even maceration, unless you macerated it for the 57 days an dried it also just before measuring. One other comment - maceration works at different speeds depending on how warm the water is. A mature bear skull could probably be macerated for a year at room temperature without many loose bones - perhaps only teeth falling out and the jaw separation occuring. The same skull at 102-105 degrees, the official suggested maceration temperature, might have the same separation in two weeks. Mature deer skulls also will only loose teeth and dentary separation with an occassional nasal or premaxillae bone falling off, where a young deer will fall apart into 40-50 individual bones because the sutures haven't closed yet.
Get the book destructive preservation by Stephen Williams which discusses various methods of bone preservation. I can only find it for sale at http://www.nhbs.com/xbscripts/bkfsrch?search=120478. in England. It is a dissertation by Dr. Stephen Williams dealing with bone preservataion, conservation and preparation. Cost is $ 22.95 GDP with shipping might be 40-50 dollars.
And that's why it's good to post questions in a generic fashion rather than to one person. For the extra views. Thanks for chiming in PA - I was hoping you would! =)
I use the simmering method and have cleaned hundreds of skulls, mostly deer and bear. I was curious myself as well as some of my customers as far as shrink is concerned, so i started green scoring and finish scoring a few. I green scored a couple B&C book and a few B&C awards bear skulls to see. I was expecting to see quite a bit of shrink , but to our surprise it always came out the same with only 1/16 in length and 1/16 in width. And my finish scoring held up with what buck and bear and B&C scored them at. That's only a grand total of 1/8 in all. Any skull is going to shrink some , even with beatles. I have been disappointed in all the bashing my method has received on here because i feel alot of people who talk about shrink by my method have never checked it out for themselves, only believing what they hear. Since I am on the subject i want to comment on people saying simmering will weaken the bone. That is probable true, but so what. If you are just going to hang it on the wall or set it on a shelf does that matter. It might matter if you are going to play catch with it or use it for a soccer ball, but otherwise my weakened skulls are surely going to outlive me and I bet you too. Ultimately what matters is what my customers think. I could go on about this. I didn't have time to address this issue earlier because i was too busy with my work. That is good! I have a growing customer base, do work for a number of taxidermist besides, most of my customers are repeaters and new customers come by word of mouth. I must be doing something right. I have YET to have a disappointed customer who wanted a discount or his money back. I am only saying these things to make a point. If the customer is happy so am I. and i am rewarded for it $$. And the method is simmering!
Thanks alot for hearing me out. I have read everyone of your post and have learned alot, thanks Raven and Taxidermologist and any others. Thanks George , Bill , Ken & WASCO etc. Skullery...Jeff..<><
There are lots of ways to beat the system! I wasn't looking for that, and now I'm almost sorry I asked the question in the first place. As an official measurer, if I have any doubt on anything, you can bet B&C and P&Y will be informed and they will deal with it appropriately. My concern from the beginning was not to be too hard on the skulls. Just 1/32" which dictates going to nearest 1/16" when measuring skulls can make the difference of making the book or not, being a new state record or not. The only consolation to this, is that if it needed to be remeasured by a panel in the case of awards or a new record, the score would be different down the road and their decisions would be final. Raven don't sell yourself short. I value your opinion which is why I asked for it in the first place.
Not to pick on Steve (taxidermologist) but the method he is suggesting would probably border on un-ethical, however people have done crazier things to get into the record book. The book calls for a sixty day "drying time" and ethically that should be adheared to. Another issue with using amonia, which some universities do now, is a permanent yellowing of the skull.
The issue of shrinkage is a huge issue in bear skulls and as Wayne said 1/32 can make a difference. I have several record book black, brown and grizzly skulls in house who's owners never fail to call around the 60 mark. They are scared to death the head has shrunken an inch during cleaning. I began keeping a log of bear shrinkage and have found with beetles it is 1/8 or less (sample size 125). There does seem to be a correlation between age and shrinkage, with younger specimans experiencing a greater rate than a mature specimen. Sinca all record book heads are generally fairly old, it makes no difference.
It is good to have actual data presented here concerning the changes that occur between green and finished skulls. The only thing I would wonder is if all your specimens were very fresh vs. dried even for a few days before shipping them to you. It could easily be predicted that juvenile/immature specimens would shrink much more because the sympheses are still growing. It is this that allows the individual bones to fall apart during maceration or simmering/boiling.
I do take umbrage at your assertion that ammonia causes yellowing of the skull. I have not found this to be the case WHEN it is thoroughly degreased to begin with. A one-week soak is not sufficient unless you use very high ammonia concentrations, i.e. industrial concentrations like the Smithsonian uses - which I do not wish to use. To completely degrease a large specimen with ammonia, much time is required - probably too much for a commercial operation. I however do not do commercail work. Secondly, if gasoline, mineral spirits, acetone or another solvent of that sort is used, one must deal with the waste product created in an ethical manner. Dissolving the fat out with gasoline creates at least a gallon of material that must be considered a toxic waste. I have taken to a brief maceration following dermestid cleaning to degrease my very fat large skulls, unless they are juveniles, where I use ammonia or in recent cases 95-99% reagent grade ethanol (contains no denaturing agents).
To Jeff, I would hope you do not take this the wrong way. Boiling or simmering has certainly got a bad rap here on the taxidermy.net. It is certainly a valid method one can use to prepare skeletal material from vertebrate material but in my eyes it is also an inferior method. Hopefully I will not offend you here, and ultimately I am sure that any statement I make will have no impact on your money-making ability in this field. I, as almost anybody who considers themselves an osteologist, started out with boiling when in my teen years back in the 1960's. I still have many skulls prepared by that method - but they are imperfect in a few ways, just as the method itself is imperfect.
I would like to point out a few of the problems in greater detail than has been placed in the archives before, though some have been mentioned.
1). First off, heating the bone material will damage the collagen to a certain degree. Mr. Conley alluded in a previous post to its total disassociation at 212 degrees, but I would bet there is definite unraveling even above 160 degrees. Other components of the bone can also be broken down besides the stress of expanding the bone by raising the temperature and then lowering it. Cracks or deviations form the norm can occur. This can best be seen by attempting to clean a turtle shell by boiling. Just for fun try cleaning a snapping turtle by boiling - initially measuring it in a green state. When finished it won't have near the same shape.
2). This procedure you may not follow, but in my opinion, any use of an additive to the boiling bath will potentially cause damage. The use of washing soda is replete in the archives. However, it is my view that utilization of any chemical including the ion Sodium will cause replacement of the Calcium ion in the bone material. In the chemical heirarchy of ion reactivity, sodium is near the top, and definitely above calcium. When you use bleach or washing soda or even similar material containing sodium, I am convinced that the chalking is caused by the ion replacement. It also weakens the bone material. The chalking can be removed by steel wool or light sandpaper, but it should not need to be done that way. Ammonia is below Calcium and even very long term soaking in weak ammonia will not cause chalking.
3). The skull is never completely cleaned with boiling. There is absolutely NO WAY all of the nerves, blood vessels, dried congealed blood, or even snot is completely removed from a boiled skull. If you look into the nasal cavity of a completed bear skull there will always be material left behind. In fact, as a beginner, when I boiled skulls, I noticed this and would often remove the nasal bones because they attracted wild dermestid species that fed on the remains of the tissue. I was horrified at the age of 10 when large beetles appeared in my personal skull collection in the basement - What if my MOM found them - would she force me to throw them out?
Chemical maceration, primarily popularized by use of biz in an article by Clair Ossian in 1970 or so, became a method used by many to clean skulls/skeletons without boiling or beetles or stinky bacterial maceration. I encountered a user of the method in 1980 or so at the University of Pittsburgh's Anthropology Department when I was helping a friend establish a colony there. He complained that he also got secondary infestation by bugs using this form of chemical maceration.
Boiling will get off 95-98% of the material, but there will always be the remaining material, which will be a magnet to draw bugs into your customers home. While granted, flour and cereal or grain products like macaroni are also bug magnets; they didn't sell a service, which added a new one to the mix.
4). Lastly, and here I am not sure of this, but I believe the simmering/boiling of the skull will set the fat within the bone. Inside bone material, especially long bones, there is fat and marrow material, as this is the site of blood cell manufacture (if I remember right). When you raise the temperature you mobilize the fat to become more fluid and impregnate the bone material. Think of it this way. Candle wax at room temperature set on a piece of paper will not impregnate the paper. However, if you heat the wax with a candle it will seep into the paper and become set there. It can be removed but it is much more difficult than when it sat inside the open area. In the typical situation, there are blood vessels and other holes going into these areas to exchange blood or for fat deposition. Solvents can much easier remove the fat by direct access, than to have to dissolve out the fat from within the bone. Most articulation experts will drill additional holes in long bones of larger mammals to allow escape of the marrow. A Bison femur can have as much as a cup of fat held within it - boiling will not help to remove it easily.
I must state that these are just my current beliefs, and you can surely debate me on whatever grounds you wish. Discussion/debate is healthy, especially when empiracal evidence is given. Boiling certainly is a method in wide use, and some very good osteologists swear by the method. I, however, prefer dermestid beetles, generally followed by soaking in ammonia for small skeletons of which I have done thousands. On all larger skeletons, I have gone the way of maceration following the initial cleaning as it allows bacteria to get into the long bones and eat away the fat/tissue without the use of a solvent. It also removes any vestige of "edible" material where the smallest instars cannot reach top consume.
In my own work I utilize most, if not all, the same techniques The Taxidermologist has mentionned above and have listed those techniques as well in a bunch of my posts. I generally do just maceration now, but used to do as mentionned above and followed a dermestid cleaning with maceration for the exact reasons The Taxidermologist listed - you get a more thorough cleaning internally. The only reason I skip the dermestids now is because of a colony crash I had a couple of years ago. None of my bone work is required to be done fast - so the quick stripping of flesh with dermestids is something I have the current luxury of doing without.
And just to confirm (with a second opinion only tho - sorry) the above theory - yes the heat does set fat into the bone. Watch a skull that has been simmered to ease flesh removal and then macerated vs a skull that has had no heat added to it before degreasing and you will likley notice a yellowing over time. Take pictures every three months over 4 years or so and you can likely notice changes in appearance that without photos you would probably not notice out of familiarity. I wish I had photos of that process with some skulls I have here. I reproduced some of them and painted them to an exact colour match a long time ago.. now the repros and originals look completely different!
Another problem with leaving oils in bones is something I referred to in a post about grease burn on capes a few days ago. Fats left inside bone can turn rancid, then acidic. Those acids can deteriorate a bone from within resulting in reconstruction, consolidation and preservation work needing to being done.
As a side note for those who like to whiten skulls... As of yet I haven't found a way to reliably KEEP skulls whitened once oils have been heat set into them. Much like on oily trout head.. every fix I have tried seems to be temporary. Thoroughly cleaning the oils out in the first place is key. By bacteria, enzyme or solvent - I guess that is open to interpretation, but the degreasing is critical regardless of the method employed. Heat can greatly reduce the chances of getting that critical degreasing done properly. I love the analogy of the candle wax btw... brilliant comparison! I have to start maintaining logs and notes on all osteological matters I suppose. I should have done that when The Taxidermologist told me to a couple of years ago - LOL! You were right Stepehen! ;) but for now suffice it to say that I have experienced the same findings that The Taxidermologist noted... so if that helps make up anyones mind one way or the other - the info is there for your assessment =)
This has turned out for me, to be a very interesting and learning experience. I have to thank all of you who have given me more information than I could have possibly of have imagined.
Stephen brought up an extremely important point. The disposal of large volumes of solvent in a responsible manner is extremely important. Since I use solvent by the drum to degrease it is certainly an environmental issue, as a matter of fact it makes me a hazardous waste generator via EPA classification (use of more than 220 lbs per month).
This caused me a lot of worries early on, but I have finally found a reliable system. By the way, the other very large osteo prep service here in Alaska simple burns his used lacquer, very illegal and if the EPA ever catches up with that would certainly put him out of business. Anyway, I found a company that delivers industrial solvent that is guaranteed to be 35% MEK. MEK is more efficient than lacquer thinner but not as efficient as Tri Chlor which you should never consider using due to the toxicity (its cost prohibitive anyway). Basically the solvent is made from recycled solvents in Washington, they deliver it to me for $110 a drum and take it back (to recycle) for $110 a drum. The cost is still 33% less than lacquer thinner for a better product.
I am currently considering investing in a solvent still (~$5000), but they are expensive. The solvent still would have one incredible advantage, it would allow me to use N Propyl Bromide. NPB is non-flammable, far less toxic and an extremely efficient degreaser, it is as close to Tri Chlor as I have found.
So, be responsible with the waste, and never stop researching the alternatives.
I forgot to mention that the reason the still would allow me to use N Propyl is that it is too expensive if I dont recyle my own. A drum is $1300 to my door, thats nearly $24.00 a gallon. It can be recycled with minimal loss, and after 3 or 4 uses restabilized.