Endurance

You gain a +4 bonus on the following checks and saves:

• swim checks made to resist nonlethal damage
• checks made to continue running
• checks made to avoid nonlethal damage from a forced march
• checks made to hold your breath 
• checks made to avoid nonlethal damage from starvation or thirst
• saves made to avoid nonlethal damage from hot or cold environments 
• saves made to resist damage from suffocation 

Also, you may sleep in light or medium armor without becoming fatigued. A character without this feat who sleeps in medium or heavier armor is automatically fatigued the next day.

Special

A ranger automatically gains Endurance as a bonus feat at 3rd level.