Isn't 8 tons a hefty estimate for Spinosaurus? I though we have had some indications that this animal from the original fossils (though sadly they are no longer with us), despite its size, was quite lightly built for its length. Are we simply scaling up from a supposed six-foot skull and coming up with an estimate based on the average weights of carnosauria with that certain head size? If so, I supposed these estimates will be a little on the extreme end until more complete specimes of Spinosaurs are found and our understanding of this genera more complete.

And one more question about the arms. Correct me, but do they seem slung too low to be easily used as effective offensive weapons against large prey? I mean this was no kangeroo and rearing up to use these arms are not as easy (I'm basing this on Stroner's Spinosaurus reconstruction)? Or is Stroner mistaken?
from Leonard, age 14, ?, ?, ?; July 27, 2001

TOM: The 8 ton estimate is based on the as-yet not described extremely large specimens of Spinosaurus aegyptiacus, and scaling up from more completely known spinosaurids (Baryonyx and Suchomimus). Incidentally, Stromer's specimen was probably not fully grown (the neural arches of its backbone hadn't fused to the centra (main body of the vertebrae): this is typical in immature archosaurs).

Also, the arms of Spinosaurus would probably do more good against creatures smaller than Spinosaurus. However, please keep in mind that Stromer's reconstruction is essentially useless: he had no more complete spinosaurids (like Baryonyx and Suchomimus) to base his model on, so he wound up with a weird T. rex-Dimetrodon combination. It wasn't his fault, though, because these more complete spinosaurid fossils weren't found until much, much later.