Thick-Skinned [Monstrous]

Your tough hide grants improved damage reduction.

Prerequisite: Damage reduction.

Benefit: Your existing damage reduction improves by 2.

Sample Damage Reductions Before and
After Thick-Skinned Feat Is Applied
DR before Thick-SkinnedDR after Thick-SkinnedTimes Applied
2/silver4/silver1
5/magic7/magic1
3/—5/—1
10/magic and bludgeoning16/magic and bludgeoning3
5/—10 (not 11; see Special)/—3

Special: You can gain this feat multiple times. Each time you take it, it improves your damage reduction by 2, up to a maximum of twice your original damage reduction.

Source: Savage Species, page 40. Completely redid the table to show better examples that adhered to the version 3.5 concept of damage reduction, including a border case.