ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris)

[peter]

(06-11-2015, 06:32 AM)'tigerluver' Wrote: @peter, I've a very important question regarding skull measurements in literature. Christiansen, using a digital method of measurement, began playing with positioning of the skull for measurement. The result seems to be his skull measurement method does not match with the conventional one in older literature. As the picture shows:

*This image is copyright of its original author

Method A is the method you have used as well as other literature from the last century I've read. Method B is Christiansen's new method. Method B looks to measure a short length. Now, have you read/met anyone who has used the method B skull position for length measurements? 

To all, examine the photos, have I made a mistake in measuring the length lines in the lower picture?

01 - The photograph of the skull was made after it was measured. The skull was photographed to compare it to others.

02 - Every skull was photographed from the same angle, but I had a different photographer every time I visited a museum. At times, it was a pro and at times it was the conservator himself.

03 - The lines in the photograph you used were drawn to show those interested in what way CBL and GTL were measured.

04 - When I measured CBL and GTL, I didn't use the complete skull. The reason is the measurement is increased when you measure CBL and GTL in this way, even when the skull is resting on a flat surface. For this reason, I decided to only use the upper skull to measure CBL and GTL.   
   
05 - The upper skull of a big cat has large canines. If the upper skull is placed on a flat surface, the result will be an angle. An angle you don't want, because it will have an effect. In order to position the teeth of the scale at the correct places and prevent angles, the skull was placed on my lap. If the CBL was measured, the skull was turned upside down. When the GTL was measured, it was the other way round. Doing it this way enabled me to work in a proper way. With the skull on my lap, I positioned the teeth of the scale at the correct places, lifted the skull to the table with the (digital) scale attached to it and measured the distance between the two teeth of the scale in full view of the one assisting me. He or she, at my request, then told me if I had placed the teeth at the correct places. The procedure was repeated three times. The measurement used was the average of three attempts. The differences between every attempt were 1-2 mm. at most. 

06 - Working in the way described above, GTL, CBL, zygomatic width, maxillary width, length of the upper canines in a straight line, width of the upper canines at the insertion of the jaw (from front to back), skull height at the orbit (with the mandibula attached to the upper skull and a horizontal scale at the top of the orbit in order to be able to measure the distance from the flat surface to the highest point of the skull) and the Pm4 were measured. Then the skull was weighed. I also added a remark on the condition of the skull (defatted or not).  

07 - After the measurements were taken, the skull was described and compared to others. Then the information on the label was noted. Quite often, I asked the conservator to assist me. The reason was most labels were old, unclear or even incorrect. If a measurement was out of the ordinary, I asked others in the museum to measure the skull. In this way, assisted by someone interested and the photographer, every skull took 30-45 minutes, at times up to 60 minutes. If a museum, for example, had a collection of 70 big cat skulls, I usually needed at least a week. For the Stuttgart collection I needed the best part of two weeks.         

08 - At home, all measurements were inserted into the tables I had prepared. The descriptions and the tables combined resulted in a document of 20-40 pages. I kept one for myself. The other was sent to the conservator, usually with a big thank you.  

09 - Before I started measuring skulls, I read everything available. Although Pocock's description was the best, it was Dr. P. van Bree who showed me how it was done. He also collected articles for me and told me about things I had to know. A great pity he had to retire. Each of the conservators had special skills, but Dr. Doris Morike (Stuttgart) was one of the most informed.   

10 - Every now and then, I visit a biologist interested in skulls to talk about the things I noticed. One of the best informed was a biologist in Belgium. He and his wife (also a biologist) got an offer they couldn't refuse just after they graduated. A bakery, that is. Bread, cake and related. But he continued collecting skulls and when I came over to measure them, he was so interested we had a debate every day. Very often, he worked on something very different. Something I didn't see. This also often happened in the museums I visited. At first, they thought I was quite mad, but nearly all conservators ended up sitting next to me. They were as interested as I was.

11 - The above suggests measuring a skull wasn't a piece of cake. If I would say it compared to fysical labour, I would be close. I know many of today's biologists measure skulls in another way. They don't go to museums anymore, but ask their peers for photographs and get them. Excellent photographs they are, way better than the ones I have. But I always wondered how they do it. I mean, I just can't imagine measuring a skull in this way. I think you need to have a skull in your hands in order to get to an idea. When I say I like skulls of wild Javan tigers best, I have a reason for it. It's difficult to explain, but there is a reason. But today is the day of limited dimensions and I guess measuring a skull by using a few photographs would fit in quite nicely.

12 - As for the question regarding Christiansen and the new way to measure skulls. You can learn how to play the guitar by reading a book, but you also could start playing right away. Everything you discover is yours. Doing it in this way will help you understand things that can't be explained. The best, I think, are the ones who did it that way. Not because they have more skills, but because what they do has more weight (meaning). And this you hear right away. And then there is playing in a team and knowing what to do or don't. Everything that matters has no shape. You can't see it and you can't touch it, but it is there and it is crucial.

But I don't doubt that Christiansen will prove me wrong. I read a number of his articles and thought they were both very interesting and well over par. He can play the guitar, but it seems to be one I don't know.                  

This post took me some time, but it was worth it. I've never explained how I measure skulls. Explaining it was interesting in that I became aware of things I wasn't aware of. When things are unclear, say so. I'll do my best to get to a clear answer. Reply