Dinosaur, Tyrannosaurus
This bipedal dinosaur's front arms seem small compared to the rest of its bulk, but its enormous head is all teeth.

Tyrannosaurus (CR 9; XP 6,400)
N Gargantuan animal
Init +5; Senses low-light vision, scent; Perception +37
Defense
AC 21, touch 7, flat-footed 20
(+1 Dex, +14 natural, –4 size)
hp 153 (18d8+72)
Fort +15, Ref +12, Will +10
Offense
Speed 40 ft.
Melee bite +20 (4d6+22/19–20 plus grab)
Space 20 ft.; Reach 20 ft.
Special Attacks swallow whole (2d8+11, AC 17, hp 15)
Statistics
Str 32, Dex 13, Con 19, Int 2, Wis 15, Cha 10
Base Atk +13; CMB +28 (+32 grapple); CMD 39
Feats Bleeding Critical, Critical Focus, Diehard, Endurance, Improved Critical (bite), Improved Initiative, Iron Will, Run, Skill Focus (Perception)
Skills Perception +37; Racial Modifiers +8 Perception
SQ powerful bite
Ecology
Environment forest, jungle, plains
Organization solitary, pair, or pack (3–6)
Treasure none
Special Abilities
Powerful Bite (Ex) A tyrannosaurus applies twice its Strength modifier to bite damage.

The tyrannosaurus is an apex predator that measures 40 feet long and weighs 14,000 pounds.

Tyrannosaurus Companions
Starting Statistics: Size Medium, Speed 30 ft.; AC +4 natural armor; Attack bite (1d8); Ability Scores Str 14, Dex 16, Con 10, Int 2, Wis 15, Cha 10; Special Qualities low-light vision, scent.

7th-Level Adv.: Size Large; AC +3 natural armor; Attack bite (2d6); Ability Scores Str +8, Dex –2, Con +4; Special Qualities grab, powerful bite.