Disproportionate

Earlier I stated that it's -2 to hit the "skull" or brain on a T-Rex.

That's because the "skull" hit location that gives the x4 damage for hitting the brain is normally a -7 to hit and a T-Rex is a big critter with a +5 to hit it.

The rules as written appear to have proportions as a constant built into them.

The thing is, despite being a LOT bigger than a human, its brain is just about the same size.  Proportionately, it's much smaller.  They're probably not as smart because a bigger critter does need a bigger brain just for housekeeping, so it's still a teeny brain.  Though it might be smarter than thought just a few years ago because we're learning that avians have a different neuro-density and structure than mammals.

Because the speed/size/range table is in absolute sizes rather than relative sizes, it should be a -7 to tag a Rex in the computer.  You'd also have to have learned where in the ginormous noggin the brain was located too.





Thanks Internet!

That animation also shows why an eye shot doesn't do the bypass skull DR to hit the brain too.