I recently reread Dubach (1981), “Quantitative analysis of the respiratory system of the house sparrow, budgerigar and violet-eared hummingbird”, and realized that she reported both body masses and volumes in her Table 1. For each of the three species, here are the sample sizes, mean total body masses, and mean total body volumes, along with mean densities I calculated from those values. House sparrow, Passer domesticus , n

I don’t have time to write about this properly, but a few people have asked me about the new Sellers et al. (2012) paper on measuring the masses of extinct animals — in particular, the Berlin Giraffatitan — by having a CAD program generate minimal complex hulls around various body regions.

Why we do mass estimates Mass estimates are a big deal in paleobiology.

As often happens here, a comment thread got to be more interesting than the original post and ended up deserving a post of its own. In this case, I’m talking about the thread following the recent Mamenchisaurus tail club post, which got into some interesting territory regarding mass estimates for the largest sauropods.

Lovers of fine sauropods will be well aware that, along with the inadequately described Indian titanosaur Bruhathkayosarus , the other of the truly super-giant sauropods is Amphicoelias fragillimus .  Known only from a single neural arch of a dorsal vertebra, which was figured and briefly described by Cope (1878) and almost immediately either lost or destroyed, it’s the classic “one that got away”, the animal that sauropod

Here’s a skeletal reconstruction of Alamosaurus modified from Lehman and Coulson (2002:fig. 11). I cloned the neck and rotated it a few degrees to see where it would put the head. The skeleton in the figure is scaled to the size of the individuals in the Smithsonian and at UT Austin.

I made this, just for the heck of it. The critters are, from left to right: OMNH 53062, the holotype of Sauroposeidon proteles , with a reconstructed skeleton grayed in; HM XV2, a fibula of Brachiosaurus brancai , which represents the largest known individual of Brachiosaurus ; HM SII, the nearly complete mounted composite skeleton of Brachiosaurus brancai in Berlin; a 20-foot-tall, world record giraffe;