Viper

Presented here are the base animal statistics for all of the most commonly used familiars-of course, these statistics can also be used for normal animals as well. Small animals like these use Dexterity to modify Climb and Swim checks.
 

Viper (CR 1/2)

Tiny Animal
Alignment: Neutral
Initiative: +3
Senses: Low-Light Vision, Scent; Perception +9
  Speed: 20 feet, Climb 20 feet, Swim 20 feet
Space: 2-1/2 feet
 

Defense

Armor Class: 16, touch 15, flat-footed 13 (+3 Dex, +1 natural, +2 size)
Hit Points: 3 (1d8-1)
Saving Throws: Fort +1, Ref +5, Will +1
 

Offense

Melee: bite +5 (1d2-2 plus poison)
Reach: 0 feet
 

Statistics

StrDexConIntWisCha
4 (-3) 17 (+3) 8 (-1) 1 (-5) 13 (+1) 2 (-4)
Base Attack Bonus: +0
CMB +1
CMD 8 (can't be tripped)
  Feats: Weapon Finesse
  Skills: Climb +11, Perception +9, Stealth +15, Swim +11 Languages:
 

Special Abilities

Poison (Ex)

Bite-injury; save Fort DC 9; frequency 1/round for 6 rounds; effect 1d2 Con; cure 1 save.
 

Ecology

Environment: Any Temperate or Warm
Organization: solitary
Treasure: none

  Vipers are not particularly aggressive snakes, but their poisonous bite can be deadly.