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

[peter]

GrizzlyClaws\ dateline='\'1424033135' Wrote: Even the fossil lions have the exact same feature.

Maybe this trait that was developed by the steppe big cats since million years ago?

*This image is copyright of its original author

ON CANINES AND SKULL CONSTRUCTION

I remember our discussion in AVA, but have to add I never paid attention to the structure of canines when I measured them. Here's what I know about canines and big cat skulls.

1 - There's no question tigers have longer and thicker canines than lions. I know some think tiger canines are a bit more slender, but that isn't true. I measured the diameter at the insertion and concluded tigers, both absolutely as well as relatively, have thicker canines. The impression regarding 'slender' is a result of the length, I think.  

2 - Teeth are made of living tissue. Like all other teeth, canines need to be nourished. For this reason, they have a canal for blood vessels and nerves in the centre. In the old days, canines in big cat skulls were at times sawn off or cut in half in order to prevent injuries. I saw it more than once and concluded the canal wasn't always visible in tiger canines. It could be the construction in tiger canines is a bit different. They seemed more ossified and, generally, denser, but I could be wrong.

3 - In tiger skulls, the upper canines are projected more downward than in lion skulls. As a result of a more vaulted upper skull, the angle often is very acute. For this reason, the upper canines function as daggers. More so than in lion skulls, they are weapons made to puncture deeply and cause lethal damage as quickly as possible.

In lion skulls, the maxillary bone (or snout) usually is longer and much more horizontal in shape. The angle of the upper canines is much less acute. In my opinion, they serve as tools to grab foremost. For this reason, perhaps, they often are a bit sharper at the tip. The difference in diameter between the tip and the most massive part of the upper canines is more outspoken in lions. Tiger canines show less difference in diameter at both ends.  

4 - Longer canines need more room. As the upper skull in tigers is usually more vaulted, the upper canines also are more vaulted. Tiger skulls, in my opinion, were constructed to serve as anchors for the canines and the muscles needed to move the jaw.

Lion skulls are a bit more massive in the centre in order to be able to withstand damage from struggling prey animals or blows from competitors). In tiger skulls, potential damage is limited as a result of the steep angle (a principle also used in tanks). Thickness or angle to protect, that is the question.

5 - Tiger skulls are very functional in that they have a vault needed for both penetration and protection; long and strong canines to overcome resistance as soon as possible; a wide rostrum for accomodate and support the strong canines and a robust sagittal crest in order to accomodate the muscles needed to move the jaws and strike with utmost force at the tips of the canines.

Lions skulls also are very functional. They seem constructed to impress, hold and limit damage, not by a clever construction, but by more mass in those regions most often targeted. In this respect, they are closer to bear skulls. Tiger skulls are more rounded and catlike, meaning they are as functional and light as they come. The reason is a hunter has no need for heavy all-weather constructions: too costly.

6 - One could argue lions, for the reasons mentioned above, didn't evolve as typical cats (hunters) and be right: the bones say lions sacrificed some of the typical features of cats in order to be able to occupy more open terrain (relatively or absolutely longer and stronger limb bones) and compete with other lions (which means they needed a relatively large, impressive and reinforced skull). Hunting, following this theory, would come second. And it does. For male lions. But females also developed flat and long skulls and they do most of the hunting. Meaning we have problem. 

My guess is both big cats, in spite of all similarities, are slightly different animals. Always were. I don't know if tigers, jaguars and leopards are different from lions or if tigers are different from the other three. I would opt for the last possibility, but there's very little to support that choice.  

PHOTOGRAPHS OF PANTHERA LEO, PANTHERA SUMATRAE AND PANTHERA TIGRIS ALTAICA

a - Wild male lion

One of the longest (greatest total length 384,55 mm., zygomatic width 259,90 mm.) and heaviest (1.840 kg.) I saw. He also had the longest canines (63,30 and 62,80 mm.):

*This image is copyright of its original author

b- Wild male Sumatran tiger

Way smaller, but, at 321,72 mm. in greatest total length and 224,80 mm. in zygomatic width, large for Sumatra and also quite heavy (1,500 kg.). Upper canines 65,30 and 65,70 mm.:  

*This image is copyright of its original author

c - Captive male Amur tiger

Greatest total length 368,60 mm. and zygomatic width 243,52 mm. Weight 2,120 kg. and upper canines 71,90 and 70,80 mm.:

*This image is copyright of its original author

All 3 skulls were in good condition. It is about the difference in structure. Everything written above, I think, was borne out by the photographs, but it could be you see something very different. If so, don't hesitate to post about it.

I once witnessed a vet removing a molar affected by an inflammation in a male tiger thought to be more or less Sumatran. At just about 8 feet in total length and 120-130 kg., he was the size of a large wild male Pantanal jaguar. The molar removed was immense in size and it took a lot of work. The vet had to abandon the attempt to get it out in one piece.

The brothers of the male tiger suffering from the inflammation watched the entire operation with a lot of interest. Same for me and others watching. One of these was so busy assisting the vet, he didn't notice he was pushed away from the bars by one of the brothers watching. It was done in a gentle way. He thought I did it and turned aroung to smile. I said it wasn't me and also smiled. My guess is he didn't believe me. Reply