Jagendar (CR 4)

Large Animal
Alignment: Always neutral
Initiative: +3 (Dex); Senses: blindsight 60 ft. and low-light vision

AC: 15 (+3 Dex, +2 natural), touch 13, flat-footed 12
Hit Dice: 7d8+14 (45 hp)
Fort +7, Ref +8, Will +2
Speed: 60 ft., climb 30 ft.
Space: 10 ft./5 ft.
Base Attack +5; Grapple +14
Attack: Bite +9 melee
Damage: bite 2d6+5
Special Attacks/Actions: Improved Grab
Abilities: Str 21, Dex 17, Con 15, Int 1, Wis 10, Cha 4
Special Qualities: resistance to poison (+4)
Feats: Endurance, Improved Natural Attack (bite), Run
Skills: Climb +14, Jump +17, and Move Silently +12
Advancement: 8-12 HD (Large)
Climate/Terrain: Underground
Organization: Domesticated
Treasure/Possessions: None

Source: Dragon #345

Blindsight (Ex): Jagendars navigate by sound, with hearing keener than even a bat's.

Improved Grab (Ex): To use this ability, an jagendar must hit with its bite. It can then attempt to start a grapple as a free action without provoking an attack of opportunity. If it wins the grapple check, it establishes a hold on the creature with its mouth. Each round it maintains the hold it deals automatic bite damage.

Favored by drow, jagendars use their snapping jaws to hold enemies still while their riders attack.