Goodman and colleagues found that skull measurements in specimens they identified as C. spelea were 1.07 to 1.32 times as large as in adult C. ferox, and postcranial measurements were 1.19 to 1.37 times as large.[3] The only specimen of C. spelea in which condylobasal length (a measure of total skull length) could be ascertained measured 153.4 mm (6.04 in), compared to a range of 114.5 to 133.3 mm (4.51 to 5.25 in) in adult C. ferox. Humerus (upper arm bone) length in twelve C. spelea is 122.7 to 146.8 mm (4.83 to 5.78 in), averaging 137.9 mm (5.43 in), compared to 108.5 to 127.5 mm (4.27 to 5.02 in), averaging 116.1 mm (4.57 in), in the extant fossa.[18] Body mass estimates for C. spelea range from 17 kg (37 lb)[19] to 20 kg (44 lb),[20] and it was among the largest carnivores of the island.[21] By comparison, adult C. ferox range from 5 kg (11 lb) to 10 kg (22 lb).[22]