SRD:Dire Rat

Dire Rat
Dire rats are omnivorous scavengers, but will attack to defend their nests and territories.

A dire rat can grow to be up to 4 feet long and weigh over 50 pounds.

Combat
Dire rat packs attack fearlessly, biting and chewing with their sharp incisors.

Disease (Ex): Filth fever—bite, Fortitude DC 11, incubation period 1d3 days, damage 1d3 Dex and 1d3 Con. The save DC is Constitution-based.

Skills: Dire rats have a +8 racial bonus on Swim checks. Dire rats have a +8 racial bonus on Climb checks and can always choose to take 10 on Climb checks, even if rushed or threatened.

Dire rats use their Dexterity modifier for Climb and Swim checks.

See Wikipedia Entry: Rat