Trackers are a type of Swampfolk found in Fallout 3's fourth DLC Pack; Point Lookout. They are a deformed version of human, likely due to Radiation and inbreeding. Trackers are similar in appearance to Bruisers. They can be identified by their different colored shirts and Bruisers are covered in more blood.
Trackers can't use guns due to their deformed hands. They will attack with either an Axe or Unarmed, either way their attacks can be very damaging to your health. A Tracker's endurance is higher than a Deathclaw or a Sentry Bot. Luckily, they are very slow and they don't have any ranged attacks making them easy pickings as long as you keep moving while you attack.