American Lion (Panthera atrox)

[tigerluver]

Last I checked Dr. Wheeler had LAC 2907-R-2 as the largest specimen in their collections (Wheeler and Jefferson 2009). Using a single Christiansen and Harris on midshaft width (did not use any other measurements), they went with a mass of ~450 kg for this specimen. This specimen is very robust, although a little bit shorter than a longer, less robust bone in LAC2907-R-3.

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The giant skeleton they have is likely not an exact replica of either of these specimens, but rather an extrapolation based on a smaller female skeleton found in the tar pits. All body mass estimation methods are not perfect and thus a range of 380-450 kg for these giant American lions would incorporate most estimates and their error. Bone width estimations get difficult because some Pleistocene animals disproportionately widened some parts, such as the diaphysis in the cursorial P. atrox, causing some measurements to overestimate and others to underestimate. When this uncertainty is exposed to the volatility of the scale factor, people find it hard to agree on a mass. Reply