So, I felt measuring the volume of some of the dinosaur's torso's, to see what they should realistically have has health. These would be slightly lower in the actual game, since I didn't bother accounting for the sloping shape of each creatures torso, this would have the greatest effect on the Shant, but even that wouldn't be lowered all that significantly.
Why the torso? Why not the whole body? Well for one, it's easier to calculate, but primarily, it's because that's where almost all of the vital organs are (except the brain). It wouldn't matter how intact your tail is if your body has been blown up.
Now, these are in cubic millimeters based off of my monitor. Your results may vary, but the proportions matter more so.
Spino: 9,061 (which is coincidentally only ten lower than the actual health)
Maia: 13,608 (surprisingly)
I'll add more dinosaurs later.