n gargantuan animal 

Perception +17; low-light vision, scent (imprecise) 30 feet

Skills Athletics +20

Str +7 Dex +0 Con +4 Int -4 Wis +4 Cha -2

Deep Breath The giant snapping turtle can hold its breath for 2 hours.

AC  28; Fort +19, Ref +15, Will +19

HP 170

Speed 20 feet, swim 40 feet

Melee [>] jaws +22, Damage 2d12+10 piercing plus Improved Grab

Capsize [>] (attack, move) The turtle tries to capsize an adjacent aquatic vessel of its size or smaller. The turtle must succeed at a DC 35 Athletics check (reduced by 5 for each size smaller the vessel is than the turtle) or the pilot's Sailing Lore DC, whichever is higher.

Shell Defense [>] The snapping turtle retracts its limbs and head into its shell and ends its turn. This increases its AC to 30, but it can't act except to reemerge, which it can do as a single action.

Swallow Whole [>] Large, 2d12+7 bludgeoning, Rupture 30.

Bestiary 2, page 269.