Freak Felids - A Discussion of History's Largest Felines

[tigerluver]

Despite often reading P. spelaea was more proportionately robust than modern lions, I don't find any evidence to that assertion in the data. For one, most records are of fragmented bones. For example, Dawkins et al. (1866) has a few fragments of long bones, and a handful of full bones. The fragments are wider than the comparitive material of modern cats, but the relative robustness relative to length cannot be determined as most of the bone is missing. From the few complete bones the ratios are essentially identical to the modern lion. Nevertheless, most fossils inidicate an average size a bit larger than the modern P. leo, around 230 kg. There 470 mm skull mentioned by Marciszak (2014) is exceptionally large for the species. From that, P. spelaea probably did not exceed 330 kg, a bit larger than a freakishly large modern lion.

I've more indicators on the sheer robustness of P.t. soloensis after some more research. For one, a value I did not discuss that was published by vK himself was the AP diameter of the head. It was 59 mm. That is extremely massive. Let's put it into perspective. P. leo and its clad (P. atrox, P. speleaea, P. fossilis) is at least 10%-20% relatively more robust than P. tigris in the proximal end of the femur (Dawkins et al. 1866). An exceptionally robust P. atrox specimen had an AP diameter of head of 54.3 mm and length of 455 mm, an index of 0.119. The Ngandong tiger specimen had an index of 0.123. Considering how much more slender tiger bones are, the Ngandong tiger proximal AP diameter is absurdly thick. This published AP diameter of the head also supports my personal extropolated DAW and greatst proximal breadth, as a 59 mm diameter can only be of a bone with such dimensions (beyond the fact that vK actually differentaited between DAW and distal diameter in his book). But in terms of mass estimation, I don't have enough specimens to produce a good trendline, so no number will be produced by the AP diameter of the femoral head. Another measurement published by vK was the diameter of the distal notch of 23 mm. The DAW scales about 4.5-4.8 times the notch diameter, within the range of my DAW measurement of 107 mm. 

On a good note, I was able to find a third comparitive diameter of the Ngandong tiger femur, the lateromedial diameter of the midshaft. Christiansen and Harris (2005) list this diameter at the point of least circumference. The word "least" is a bit misleading. Egi (2001) clarifies the point of measurement, which is the 1/2 point of the length of the bone (AKA the midshaft) in femur and tibia and the 55% length point in the humerus as follows:

*This image is copyright of its original author

Thus, I extropolated the third Ngandong femur measurement compatible with published databases, LM diameter of the shaft. The measure was 42 mm, much more robust than modern tigers and a bit shy of the most robust P. atrox femur. 

Thus, from the measurements of the femur length (480 mm, est. 409 kg), DAW (107 mm, est. 531 kg), and LM diameter of shaft (42 mm, 559 kg), the calculated mass of this specimen is 500 kg. 


 

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