The main species on Sheeponia is the Sheeponian, a very tall sheep with a humanish face.
It is a simple being that live on grass and follows the herd. The species is not particularly intelligent, although its leader, Adam Harpe (who claims he is an aferior being), is able to represent his race and moon in official meetings (So far there has only ever been one meeting requiring his presence). Adam Harpe is not actually a Sheeponian. He was originally a Gian, who was abandoned at birth on Sheeponia and grew up thinking he was a Sheeponian. He learnt their way of life but has been in contact with Gians, and so he has learn some English. He can communicate with people and translate for the sheeponians. This has provided the Interplanetary Governing Body with vital information about their race.