The Thraka-Hai, also known as Girmushi were a specialized Breed of lesser Orcs from Mordor.They were the smallest known kind of Orc, sometimes only 3' tall, of light grey or sallow skin, with large bulbous eyes and long ears.They were weak as fighters or laborers but incredibly swift and dextrous.Fast runners, silent and very sharp-sensed they were bred as Scouts, and sometimes even Snipers or Assassins.Larger Orcs often referred to them as "Ploshati" , "Fleas".
The Rangers of Ithilien on first sight mistook the degenerated Stoor named Gollum for a member of this orc-kind.
See: Orc-Trackers