However, his method (actually Preuschoft's)
depends on what seems like a very questionable assumption, namely that the habitual posture of an animal's neck is the one that most nearly equalises the stress exerted on the intervertebral discs. I can't for the life of me see why this should be true. If a useful posture entails more stress on intervertebral joint A than on B, the animal is hardly likely for that reason to favour a posture in which the stress on B is _increased_ to match that on A.
To be fair to Christian 2002, though, it does apply the method to a couple of extant critters
Giraffe, camel.
"In the late 40s, it was felt by some academics that Britain would need 3 or 4 computers, and the US 6 or 7. Unbelievable but true. Those early computer pioneers certainly were morons" -- Andrew Brand.