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Skulls, Skeletons, Canines & Claws
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 (10-30-2016, 05:11 AM)GrizzlyClaws Wrote: Here at the post #90 is a holotype of a set of three lion canines (two upper and one lower) with all details available. Density is based on volume, which is 3-d, thus mass must be divided by a cubed measurement (ie. mm^3). Usually we have three measurements on canines, length, width, and depth, at best. So here are 3 ways we can get an actual density value with a cubed unit. I'll use the superior lion canines referenced in @GrizzlyClaws post to show the math. You could divide the mass of the canine by the cube of its length: Canine density = canine mass/(length)^3 Canine 1: 51.6 g/(106 mm)^3 = 4.33e-5 Canine 2: 51 g/(105^3) = 4.40e-5 You can substitute any other measurement and cube that as well. However, as this calculation takes into account only one measurement and forces a cubed value out of it, it is the least accurate. Another way could be to force a cubed unit out of two measurements. You can take the length and multiply it by the square of a width/depth measurement as follows: Canine density = canine mass/(length * width^2) Canine 1: 51.6 g/(106 * 29^2) = 5.79e-4 Canine 2: 51 g/(105 * 28^2) = 6.20e-4 More accurate the previous method as two dimensions are working to create a 3-D model. Finally, you can use a length, width, and depth measurements to get a cubed measurements without forcing anything as the last two methods did: Canine density = canine mass/(length * width * depth) Canine 1: 51.6 g/(106 * 29 * 20) = 8.39e-4 Canine 2: 51 g/(105*28*20) = 8.67e-4 This would be the most accurate out of what is in this post as you actually dividing a mass by a true volumetric measurement. Of course, you could buff density accuracy in others ways, but that's too complex for what we need here. The tiger canine referenced unfortunately only shows to measurements (length = 103 mm; width = 32 mm). We have to use the second method for comparison with the lion canines. Tiger canine density = 70 g/(103 * 32^2) = 6.64e-4 The two lion canines average to 6.00e-4 for the same measurement, which is ~10% less dense. The actually discrepancy can still be different, as we forced a 3D measurement in this case and did not account for canine depth. We did not account for the way each canine is shaped either. 
@tigerluver
Thanks a lot for explaining everything with an elaborate formula, that's what I explained before, the density is correlated with the volume. When both specimens are older males with the solid canines, only the volume would determine the density.
Brown bear claws
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Asiatic Black bear
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 (10-31-2016, 03:33 AM)GrizzlyClaws Wrote: @parvezThat is interesting. I mean the way the hollowness reduces with age. In humans I assume they become weak with age meaning the cavity may not decrease atleast with age. May be the experience and expertise of using them makes them harder leading to decrease in hollow space. It seems there is a rhythm in nature through which canines become robust, the rythm may be achieved only through invincibility through whatever they face including competitors, surroundings, prey etc Only if emerged victorious invincibly through this long process the offspring of this successful animal seem to develop compact canines. Leapords seem to fail through this process as they are relatively weaker than jaguar, lead style of escaping bigger predators like lion and tiger. Though they are top predators in some eco systems their instincts does not seem to fade away like fearing bigger predators. That may be the reason for their slender canines. At least for some reason they are unable to achieve invincibility as they may be poor swimmers or unable to hunt in water. Jaguars on other hand seem to have achieved the invincibility through whatever they came across.
@parvez
The post #120 of this thread has the sample of the sub-adult tiger canines, the inside is all fluid, not solid like the older tiger canines. Animals and humans evolved in the opposite way. The Clouded leopards also got very slender canines, perhaps for the same reason as the leopard. (10-31-2016, 10:32 AM)GrizzlyClaws Wrote: @parvez Thanks grizzly claws those canines are not fully developed. They may be the next stage to milk teeth. Just like in humans too but it Is opposite in old age as you said. Thanks for sharing. If humans were wild even today they may be having compactor canines as they became old.
These canines were still at the earlier stage of the permanent teeth. The root of the canines were still unsealed which needs more nourishment through the nervous systems. That's why the canine teeth can maintain the creamy white coloration.
After that, the root would be sealed as the cavity starts to disappear, and the canine teeth start to need less nourishment and the coloration would still start to turn yellowish.
What is the relation between coloration and sealing of cavities? Does the fluid from cavity responsible for maintaining white coloration @Grizzly claws
I think the fluid presents the blood vessels and nerves, since the young tigers may require a lot of these in order to absorb more nutrition to grow their teeth.
And the older tigers may require less nutrition for teeth growth, and the cavity becomes smaller. And with less blood vessels and nerves flow within it, the teeth could turn into the less whitening coloration. I am not a biologist, maybe @peter could provide you an even more elaborate answer. (10-31-2016, 11:52 AM)GrizzlyClaws Wrote: I think the fluid presents the blood vessels and nerves, since the young tigers may require a lot of these in order to absorb more nutrition to grow their teeth.May be the fluid helps in frequent cleaning of teeth. Hence it maintains white coloration. With the sealing of cavity the fluid cannot flow out and hence cannot help in maintaining the colour of teeth through moisturizing. Anyways peter can confirm this as you said
Brown bear canines
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Amur tiger
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